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nextnano Documentation
November 2024
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Getting Started

  • About the nextnano Software
    • Overview
    • Digital Accessibility
      • Accessibility Statement for nextnano Software
        • Conformance status
        • Feedback
        • Compatibility with assistive technology
        • Limitations and alternatives
        • Assessment approach
      • Accessibility Evaluation Report for nextnano Software
        • Executive Summary
        • Scope of Review
        • Reviewers
        • Review Process
        • Results
        • References
  • Downloads
    • FREE nextnano tools
      • Free nextnano++ package
        • Windows
      • nextnanomat GUI
        • Windows
      • nextnanopy package
    • nextnano++ package
      • Windows
        • recommended
        • stable (2023-08-07)
        • beta (2024-08-23)
      • Ubuntu
        • beta (2024-08-23)
      • Linux Red Hat Enterprise Linux 8.1
        • alpha (2024-10-31)
      • Linux Red Hat Enterprise Linux 7.6
        • alpha (2024-10-31)
      • macOS (Intel processor)
        • beta (2024-08-23)
    • nextnano++ & nextnano.NEGF bundle
      • Windows
        • beta (2024-08-23)
        • alpha (2024-09-16)
      • Ubuntu
        • beta (2024-08-23)
        • alpha (2024-05-24)
    • nextnano.NEGF package
      • Windows
        • beta (2024-09-18)
    • Advanced downloads
      • nextnanomat GUI
        • Windows (32-bit)
      • nextnano License Activators
        • Windows
        • Ubuntu
        • macOS (Intel processor)
      • Libraries for gcc releases
    • Types of Packages and Versioning
      • Installer vs Portable
      • Versions
  • Installation
    • First Steps
    • Operating system
      • Windows
      • Linux
        • Running nextnano++ & nextnano³ on Linux from Terminal
        • Running nextnano++ & nextnano³ on Linux using nextnanopy
        • License activation
        • nextnanomat GUI on Linux
        • Wine Installation
        • Troubleshooting
      • macOS
        • macOS (Intel-CPU)
        • macOS (ARM-CPU)
  • License Activation
    • License activation via command line
      • Available license file on different operating systems
      • Online and offline activation
      • Fingerprint activation
    • License activation via nextnanomat

nextnano Tools

  • 1. nextnanomat
    • 1.1. GUI tabs
      • Input
        • Autocomplete feature
      • Template
        • Variable definition in input file (required)
        • Sweep over a variable + optional post-processing
        • Post-processing of existing sweep
      • Template (Beta)
        • Introduction
        • The input file
        • How to create a sweep
        • Save input files and run a sweep
      • Simulation
      • Output
        • Navigation
        • Visualization
        • Features
        • Export functionality
        • Further information
    • 1.2. Settings
      • Options: Simulation
      • Options: Material database
      • Options: Licenses
      • Options: Editor
      • Options: View/Output
      • Options: Expert settings
      • Options: Gnuplot settings
      • Options: Custom executable
        • Example: How to run TiberCAD from nextnanomat
      • Options: Data export
    • 1.3. Main menu functions
      • Activate license
      • Convert nextnano³ input file to nextnano++
      • Clean Up Simulation Output Folder
      • Generate nextnanopy config file
      • Generate System Snapshot for Troubleshooting
    • 1.4. Color maps
      • Introduction
      • Implementation
      • References
    • 1.5. Export Functionalities
      • Exporting to ParaView
        • Setting Up nextnanomat
        • Direct Export
        • Exporting 2D Outputs with Python Scripts
      • Gnuplot export
        • How to export 1D plot files with Gnuplot
        • How to export 2D or 3D plot files with Gnuplot
        • How to optimze the looks of a Gnuplot graph
      • Export via python scripts
        • How to call custom python scripts directly from nextnanomat
      • Other
    • 1.6. Release Notes
      • 4.3.2.15 (2024-03-28)
      • 4.3.2.8 (2023-08-07)
      • 4.3.1.8 (2022-08-05)
      • EARLIER
    • 1.7. FAQs
      • Features and Functionalities
        • How do I produce 1D slices through the 2D plots in the GUI?
        • Is there a way to produce a 1D (or 2D) plot of some result, for example the probability density with the conduction band edge superimposed? In other words, can the GUI show multiple plots at once?
        • What is the difference between “List view” and “Tree view”?
        • How to prevent fonts from changing back to Calibli in the input tab?
        • How can I add additional debug information to the LOG file?
        • Can I pass additional command line arguments to the executables of simulation tools?
      • Error Messages
        • Error: File format is not valid
        • Error: The specified executable is not a valid application for this OS platform.
        • Licensing.dll cannot be found
        • Error during license activation
        • Unverified license
      • Problems and Limitations
        • The Window of the graphical user interface gets (too) small
  • 2. nextnano++
    • 2.1. Overview
      • Running
      • Input file
      • Output
      • Examples
      • Material database
    • 2.2. Models
      • Crystal Coordinate Systems
      • Hamiltonian: 8-band model for zincblende
        • The Model
        • Offsets
        • Deformation potentials
        • k.p parameters
      • Introduction to strain calculation
        • Strain tensor \(\varepsilon\)
        • Stress tensor \(\sigma\)
        • Strain and stress calculation
      • Piezoelectricity in wurtzite
        • Specify crystal orientation
        • Parameter sweep of the angle using Template: Sweep over the variable theta
        • Strain
        • Piezoelectric effect (first-order)
        • Post-Processing for polarization
        • Alloy content dependence
        • AlGaN
        • Piezoelectric effect (second-order)
      • General scheme of the optical device analysis
        • Related tutorials
        • Determination of carrier densities and current densities
        • Optoelectronic characteristics based on the semi-classical model
        • Optoelectronic characteristics based on the quantum model
        • References
      • Mobility
        • Low-field mobility models
        • High-Field Mobility Models
      • Model for optical spectra within Fermi’s golden rule
      • Doping
        • Activation Energies
    • 2.3. Material Database
      • Introduction to Material Database
        • Parameters of Elements & Binary Compounds
        • Bowing Parameters and Ternary Alloys
      • Defining New Materials
        • Database or Input File?
        • Modifying an Existing Material
        • Defining a New Binary Compound or Element
        • Defining a New Alloy
      • Interpolation Schemes
        • Introduction
        • Two-component alloys
        • Three-component alloys
        • Four-component alloys
        • Six-component alloys
        • Eight-component alloys
      • Default Materials and Alloys
        • Insulators and Metals
        • Binary alloys
        • Ternary alloys
        • Quaternary alloys
        • Quinternary alloys
      • Definition of Band Offsets (zincblende)
    • 2.4. Tutorials
      • Introduction
      • Basics
        • Defining Structures
        • Contacts and Boundary Conditions
        • Electrostatics and Strain
        • Currents
        • Other
      • p-n Junctions & Solar Cells
        • — FREE — GaAs p–n junction
        • — DEV — I–V characteristic of GaAs p–n junction | 1D/2D/3D
        • — NEW/EDU — p-n junction in the dark
        • — EDU — p-n junction under illumination
        • GaAs solar cell
        • Cascade solar cell (Tandem solar cell)
      • Light-Emitting Diodes
        • InGaAs Multi-quantum well laser diode
        • UV LED: Quantitative evaluation of the effectiveness of EBL
        • UV LED: Quantitative evaluation of the effectiveness of superlattice structure in p-region
      • Quantum Mechanics
        • Parabolic Quantum Well (GaAs / AlAs)
        • Triangular well
        • — FREE — Double Quantum Well
        • — EDU — Orbitals of the Hydrogen Atom
      • Quantum Wells
        • InAs / GaSb broken gap quantum well (BGQW) (type-II band alignment)
        • Si/SiGe MODQW (Modulation Doped Quantum Well)
        • Exciton Binding Energy in an Infinite Quantum Well
        • Scattering times for electrons in unbiased and biased single and multiple quantum wells
        • — DEV — Strain effects in freestanding nitride nanostructures
      • Quantum Wires
        • Hexagonal GaAs/AlGaAs nanowires
        • Electron wave functions in a cylindrical well (2D Quantum Corral)
        • — SOON — T-shaped quantum wire grown by cleaved edge overgrowth (CEO): wave functions without strain
        • — SOON — T-shaped quantum wire grown by cleaved edge overgrowth (CEO): wave functions and strain
      • Quantum Dots
        • Energy levels in idealistic 3D cubic and cuboidal shaped quantum dots
        • Hole energy levels of an “artificial atom” - Spherical Si Quantum Dot (6-band k.p)
        • Quantum Dot Molecule
        • Energy levels in a pyramidal shaped InAs/GaAs quantum dot including strain and piezoelectric fields
        • — NEW — Hexagonal shaped GaN quantum dot embedded in AlN (wurtzite)
        • — DEV — Energy levels of an “artificial atom” - Spherical and ellipsoidal CdSe Quantum Dot
      • Electronic Band Structures
        • k.p dispersion in bulk GaAs (strained / unstrained)
        • k.p dispersion in bulk unstrained, compressively and tensely strained GaN (wurtzite)
        • k.p dispersion in bulk unstrained ZnS, CdS, CdSe and ZnO (wurtzite)
        • Energy dispersion of holes in a quantum well
        • k.p dispersion of an unstrained GaN QW embedded between strained AlGaN layers
        • Energy dispersion of a cylindrical shaped GaN nanowire
        • — NEW — Electronic band structure of 2DHG in Silicon inversion layers under pseudomorphic strain | 1D
        • Electronic band structure of 2DHG in Si inversion layers under arbitrary stress | 1D
      • Superlattices
        • Dispersion in infinite superlattices: Minibands (Kronig-Penney model)
        • InAs / In0.4Ga0.6Sb superlattice dispersion with 8-band k.p (type-II band alignment)
        • Multiple quantum wells and finite superlattices
        • — DEV — Artificial quantum dot crystal - Superlattice dispersion (minibands)
      • Cascade Structures
        • Simple quantum cascade structure
        • Quantum-Cascade Lasers
      • Optical Spectra and Transitions
        • Single Particle
        • Excitons
      • 2-Dimensional Electron Gases (2DEGs)
        • — FREE — Schrödinger-Poisson - A comparison to the tutorial file of Greg Snider’s code
        • — DEV — Shubnikov-de Haas effect and subband occupation of 2DEG
        • Depletion of electrons in a two-dimensional electron gas (2DEG)
      • Transmission and Conductance (CBR method)
        • Transmission (CBR)
        • Landauer conductance and conductance quantization: from quantum wires to quantum point contacts
        • Electron Flying Qubit
        • — DEV — Efficient method for the calculation of ballistic quantum transport - The CBR method (2D example)
        • Transmission through a nanowire (CBR)
        • Conductance of a quantum point contact (gated two-dimensional electron gas)
      • Transistors
        • HEMT structure (High Electron Mobility Transistor)
        • Two-dimensional electron gas in an AlGaN/GaN FET
        • MOS Capacitor & MOSFET
        • Two-dimensional electron gas in a Si MOSFET
        • Electron wave functions of a 2D slice of a Triple Gate MOSFET
        • Single-electron transistor - laterally defined quantum dot
        • — DEV — Ultrathin-body DG MOSFET with 2-nm channel
        • — DEV — Ultrathin-body DG MOSFET with 5-nm channel
      • Magnetic Effects
        • Fock-Darwin states of a parabolic, anisotropic (elliptical) potential in a magnetic field
        • Fock-Darwin states of parabolic, isotropic potential in a magnetic field
        • Landau levels of a bulk GaAs sample in a magnetic field
        • Hole wave functions in a quantum wire subjected to a magnetic field
        • — DEV — Vertically coupled quantum wires in a longitudinal magnetic field
      • Numerics
        • General
        • Big 3D systems
      • Tricks and Hacks
        • C-V curve calculation for general structures (Post-processing by python)
        • Interband tunneling current in a highly-doped nitride heterojunction
        • Optical generation in InGaAs/GaAs QW
        • Photoluminescence of Quantum Well
        • From GDSII to Transmission Workflow
        • Wurtzite GaN/AlN/GaN on Si(111)
        • Automatically running processes after simulation
    • 2.5. Keywords
      • postprocessor{ }
        • datafile
        • goto_output
        • call
      • import{ }
        • directory
        • file{ }
        • file{ name }
        • file{ filename }
        • file{ format }
        • file{ scale }
        • file{ number_of_dimensions }
        • analytic_function{ }
        • analytic_function{ name }
        • analytic_function{ function }
        • analytic_function{ label }
        • analytic_function{ component{ } }
        • analytic_function{ component{ function_i } }
        • analytic_function{ component{ label } }
        • output_imports{ }
      • output{ }
        • directory
        • mandatory_path
        • set_origin{ }
        • set_origin{ x }
        • set_origin{ y }
        • set_origin{ z }
        • format2D
        • format3D
        • silent
        • write_avs_v
        • write_origin_plt
        • write_gnuplot_plt
        • use_gnuplot_one_file
        • only_sections
        • section{ }
        • section{ name }
        • section{ range_x }
        • section{ range_y }
        • section{ range_z }
        • section1D{ }
        • section1D{ name }
        • section1D{ x }
        • section1D{ y }
        • section1D{ z }
        • section1D{ range_x }
        • section1D{ range_y }
        • section1D{ range_z }
        • section2D{ }
        • material_parameters{ }
        • material_parameters{ kp_parameters{ } }
        • material_parameters{ kp_parameters{ boxes } }
        • material_parameters{ spin_orbit_coupling_energies{ } }
        • material_parameters{ spin_orbit_coupling_energies{ boxes } }
        • material_parameters{ charge_carrier_masses{ } }
        • material_parameters{ charge_carrier_masses{ boxes } }
        • material_parameters{ static_dielectric_constants{ } }
        • material_parameters{ static_dielectric_constants{ boxes } }
        • material_parameters{ deformation_potentials{ } }
        • material_parameters{ deformation_potentials{ boxes } }
      • run{ }
        • structure_only{ }
        • strain{ }
        • poisson{ }
        • current_poisson{ }
        • quantum{ }
        • quantum_density{ }
        • quantum_poisson{ }
        • quantum_current_poisson{ }
        • quantum_optics{ }
      • global{ }
        • simulate1D{ }
        • simulate2D{ }
        • simulate3D{ }
        • crystal_zb{ }
        • crystal_zb{ x_hkl }
        • crystal_zb{ y_hkl }
        • crystal_zb{ z_hkl }
        • crystal_wz{ }
        • crystal_wz{ x_hkl }
        • crystal_wz{ y_hkl }
        • crystal_wz{ z_hkl }
        • crystal_wz{ rotation_c_a_ratio_use_substrate }
        • crystal_wz{ rotation_c_a_ratio }
        • substrate{ }
        • substrate{ name }
        • substrate{ alloy_x }
        • substrate{ alloy_y }
        • substrate{ alloy_z }
        • temperature
        • temperature_dependent_bandgap
        • temperature_dependent_lattice
        • magnetic_field{ }
        • magnetic_field{ direction }
        • magnetic_field{ strength }
        • periodic{ }
        • periodic{ x }
        • periodic{ y }
        • periodic{ z }
      • impurities{ }
        • donor{ }
        • donor{ name }
        • donor{ degeneracy }
        • donor{ energy }
        • donor{ N_ref }
        • donor{ c }
        • acceptor{ }
        • acceptor{ name }
        • acceptor{ degeneracy }
        • acceptor{ energy }
        • acceptor{ N_ref }
        • acceptor{ c }
        • charge{ }
        • charge{ name }
        • charge{ type }
      • contacts{ }
        • vacuum_level
        • schottky{ }
        • schottky{ name }
        • schottky{ bias }
        • schottky{ steps }
        • schottky{ barrier }
        • schottky{ work_function }
        • ohmic{ }
        • ohmic{ name }
        • ohmic{ bias }
        • ohmic{ steps }
        • ohmic{ shift }
        • fermi{ }
        • fermi{ name }
        • fermi{ bias }
        • fermi{ steps }
        • fermi_electron{ }
        • fermi_electron{ name }
        • fermi_electron{ bias }
        • fermi_electron{ steps }
        • fermi_hole{ }
        • fermi_hole{ name }
        • fermi_hole{ bias }
        • fermi_hole{ steps }
        • charge_neutral{ }
        • charge_neutral{ name }
        • charge_neutral{ bias }
        • charge_neutral{ steps }
        • zero_field{ }
        • zero_field{ name }
        • zero_field{ bias }
        • zero_field{ steps }
        • long_directory_names
      • structure{ }
        • region{ }
        • output_region_index{ }
        • output_material_index{ }
        • output_user_index{ }
        • output_contact_index{ }
        • output_alloy_composition{ }
        • output_impurities{ }
        • output_generation{ }
        • output_injection{ }
        • structure{ region{} } - generation & electron injection
        • structure{ region{ integrate{ } } }
        • structure{ region{} } - assigning materials
        • structure{ region{} } - shape objects
      • grid{ }
        • xgrid{ }
        • xgrid{ min_pos }
        • xgrid{ max_pos }
        • xgrid{ allow_spacing_jumps }
        • xgrid{ line{ } }
        • xgrid{ line{ pos } }
        • xgrid{ line{ spacing } }
        • xgrid{ line{ array{ } } }
        • xgrid{ line{ array{ shift } } }
        • xgrid{ line{ array{ min } } }
        • xgrid{ line{ array{ max } } }
        • xgrid{ line{ array2{ } } }
        • xgrid{ line{ array2{ shift } } }
        • xgrid{ line{ array2{ min } } }
        • xgrid{ line{ array2{ max } } }
        • ygrid{ }
        • zgrid{ }
        • energy_grid{ }
        • energy_grid{ min_energy }
        • energy_grid{ max_energy }
        • energy_grid{ energy_resolution }
      • classical{ }
        • Gamma{ }
        • HH{ }
        • LH{ }
        • SO{ }
        • X{ }
        • Delta{ }
        • L{ }
        • carrier_statistics
        • energy_distribution{ }
        • energy_resolved_density{ }
        • bulk_dispersion{ }
        • output_bandgap{ }
        • output_bandedges{ }
        • output_carrier_densities{ }
        • output_band_densities{ }
        • output_ionized_dopant_densities{ }
        • output_intrinsic_density{ }
      • strain{ }
        • debuglevel
        • no_strain{ }
        • pseudomorphic_strain{ }
        • minimized_strain{ }
        • growth_direction
        • residual_strain
        • linear_solver{ }
        • import_strain{ }
        • piezo_density
        • second_order_piezo
        • pyro_density
        • output_hydrostatic_strain{ }
        • output_strain_tensor{ }
        • output_distortion_tensor{ }
        • output_stress_tensor{ }
        • output_displacement{ }
        • output_force_density{ }
        • output_elastic_energy_density{ }
        • output_polarization_charge{ }
        • output_polarization_charge_components{ }
        • output_polarization_vector{ }
        • output_polarization_vector_components{ }
        • output_lattice_constants{ }
        • output_elastic_constants{ }
        • output_piezo_constants{ }
        • output_second_order_piezo_constants{ }
        • output_pyro_constants{ }
      • poisson{ }
        • debuglevel
        • import_potential{ }
        • import_potential{ import_from }
        • import_potential{ component_number }
        • electric_field{ }
        • electric_field{ direction }
        • electric_field{ strength }
        • electric_field{ reference_potential }
        • between_fermi_levels{ }
        • charge_neutral{ }
        • newton_solver{ }
        • newton_solver{ iterations }
        • newton_solver{ search_steps }
        • newton_solver{ residual }
        • newton_solver{ gradient_shift }
        • linear_solver{ }
        • linear_solver{ iterations }
        • linear_solver{ abs_accuracy }
        • linear_solver{ rel_accuracy }
        • linear_solver{ dkr_value }
        • linear_solver{ use_cscg }
        • linear_solver{ force_diagonal_preconditioner }
        • linear_solver{ force_iteration }
        • bisection{ }
        • bisection{ delta }
        • bisection{ residual }
        • bisection{ iterations }
        • bisection{ robust }
        • output_potential{ }
        • output_electric_field{ }
        • output_electric_displacement{ }
        • output_electric_polarization{ }
        • output_dielectric_tensor{ }
        • output_dielectric_tensor{ boxes }
      • currents{ }
        • debuglevel
        • import_electron_fermi_level{ }
        • import_hole_fermi_level{ }
        • insulator_bandgap
        • electron_mobility{ }
        • hole_mobility{ }
        • recombination_model{ }
        • linear_solver{ }
        • minimum_density
        • minimum_density_factor
        • maximum_density
        • maximum_density_factor
        • minimal_recombination
        • electron_contact
        • hole_contact
        • output_fermi_levels{ }
        • output_fermi_level_difference{ }
        • output_velocities{ }
        • output_forces{ }
        • output_currents{ }
        • output_power_density{ }
        • output_mobilities{ }
        • output_recombination{ }
        • output_injection{ }
      • quantum{ }
        • quantum{ region{ } }
        • quantum{ exchange_correlation{ } }
        • quantum{ cbr{} } (optional)
        • quantum{ debuglevel }
        • quantum{ allow_overlapping_regions }
      • optics{ }
        • optics{ debuglevel }
        • optics{ global_illumination{ } }
        • optics{ global_reflectivity{ } }
        • optics{ global_absorption_coeff{ } }
        • optics{ global_refractive_index{ } }
        • optics{ light_propagation{ } }
        • optics{ photogeneration{ } }
        • optics{ semiclassical_spectra{ } }
        • optics{ quantum_spectra{ } }
      • database{ }
        • Top level keywords in database{ }
        • Nested groups in database{ …_zb{} } and database{ …_wz{} }
    • 2.6. Input Syntax
      • General
        • Case Sensitivity
        • White-Spaces
        • Semicolons
      • Variables
        • Numbers and arrays
        • Strings
      • Comments
        • One-line comment
        • Multi-line comment
      • Conditional Statements
        • Conditional lines
        • Conditional blocks
      • Data section
      • Operators and functions
        • Tables for number variables
        • Arithmetic comparisons and logical operators
        • Dealing with floating-point numbers
        • Functions for array variables
      • Debug statements
      • Groups and attributes
      • XML Tags
      • Additional Examples and Remarks
    • 2.7. Simulation Output
      • Basic information
      • Diagnostic information and error handling with log file
      • Visualization - VTK and AVS
        • VTK format for rectilinear grid
        • AVS format for rectilinear grid
    • 2.8. Command Line
    • 2.9. Maximizing Performance
    • 2.10. Release Notes
      • 1.20.8.b (2024-08-22)
      • 1.19.61.a (2024-06-28)
      • 1.19.49.a (2024-06-17)
      • 1.19.22.a (2024-05-14)
      • 1.19.17.a (2024-04-28)
      • 1.18.63.b (2024-03-24)
      • 1.17.20 (2023-08-07)
      • 1.14.33 (2023-05-12)
      • 1.13.0 (2023-02-19)
      • 1.12.35 (2022-12-17)
      • 1.10.19 (2022-08-09)
      • 1.9.92 (2022-06-08)
      • EARLIER
    • 2.11. FAQs
      • Features and Functionalities
        • Where to find simulation LOG file
        • What is the difference between nextnano³ and nextnano++?
        • Can I convert nextnano³ input files into nextnano++ input files?
        • How can I track how much memory is used during the simulations?
        • Can I pass additional command line arguments to the executable?
        • How can I speed up my calculations with respect to CPU time?
        • Can I take advantage of parallelization of the nextnano software on multi-core CPUs?
        • What boundary conditions are available?
        • What are quasi-Fermi levels
        • I do not understand the \(\mathbf{k} \cdot \mathbf{p}\) parameters
        • Can I add new materials to the database?
        • Should I use averaged outputs and boxes?
      • Error Messages
        • Quantum-Current-Poisson fails to converge
        • Error: (nodes number of coordinate 1) != (lines number in file)
        • nextnano++ exit code: -1073741795
        • nextnano++ exit code: -1
        • nextnano++ exit code: 1
        • nextnano++ exit code: 3
  • 3. nextnano³
    • 3.1. Overview
    • 3.2. Input Syntax
      • Macro features
        • Macro 1: Variables
        • Macro 2: Namelist (deprecated)
      • The input file keywords
      • Keywords
        • $simulation-dimension
        • $regions
        • $region-cluster
        • $quantum-cluster
        • $current-cluster
        • $current-regions
        • $current-models
        • $impurity-parameters
        • $material-interfaces
        • $magnetic-field
        • $Auger-recombination
        • $direct-recombination
        • $SRH-recombination
        • $mobility-model-constant
        • $mobility-model-minimos
        • $mobility-model-simba
        • $mobility-model-arora
        • $mobility-model-dar
        • $mobility-model-lom
        • $mobility-model-masetti
        • $optical-absorption
        • $buffer-solutions
        • $buffer-constant-A(T)
        • $tighten
        • $tight-binding
        • $warnings
        • $quantum-bound-states
        • $quantumstate-recombination-rates
        • $NEGF-spintronics
        • $global-parameters
        • $output-grid
        • $output-geometry
        • $output-raw-data
        • $input-filename
        • $Monte-Carlo
        • $domain-coordinates
        • $material
        • $strain-minimization-model
        • $poisson-boundary-conditions
        • $quantum-dot-layer-density
        • $output-strain
        • $output-bandstructure
        • $output-1-band-schroedinger
        • $output-kp-data
        • $output-densities
        • $output-current-data
        • $output-file-format
        • $output-section
        • $output-material
        • $doping-function
        • $interface-states
        • $global-settings
        • $simulation-flow-control
        • $grid-specification
        • $import-data-on-material-grid
        • $binary-zb-default
        • $binary-wz-default
        • $ternary-zb-default
        • $ternary-wz-default
        • $alloy-function
        • $numeric-control
        • $CBR-current
        • $quantum-regions
        • $quantum-model-electrons
        • $quantum-model-holes
        • $voltage-sweep
        • $electric-field
        • $simple-drift-models
        • $NEGF
        • $electrolyte
        • $electrolyte-ion-content
    • 3.3. Material Database
      • The database keywords
      • Keywords
        • $binary-zb-default
        • $binary-wz-default
        • $ternary-zb-default
        • $ternary-wz-default
        • $default-materials
        • $default-material-models
        • $Auger-recombination
        • $direct-recombination
        • $SRH-recombination
        • $mobility-model-arora
        • $mobility-model-constant
        • $mobility-model-dar
        • $mobility-model-lom
        • $mobility-model-masetti
        • $mobility-model-minimos
        • $mobility-model-simba
        • $mobility-models
        • $transport-models
        • $buffer-constant-A(T)
        • $buffer-solutions
        • $physical-constants
        • $input-scaling-factors
        • $global-parameters
        • $program_restrictions
        • $input_filename
        • $domain-coordinates-defaults
        • $zb-default-expectations
        • $wz-default-expectations
        • $zb-restrictions
        • $wz-restrictions
        • $region-default
        • $known-doping-functions
        • $known-function-names
        • $known-impurity-types
        • $interface-state-limitations
        • $quantum-model-electrons
        • $quantum-model-holes
        • $separation-models-electrons
        • $separation-models-holes
        • $method-of-brillouin-zone-integration
        • $k-range-determination-methods
        • $tight-binding-parameters
        • $warnings
    • 3.4. Tutorials
      • Band structure
        • Empirical tight-binding sp3s* band structure of GaAs, GaP, AlAs, InAs, C (diamond) and Si
        • Tight-binding band structure of graphene
        • 30-band \(\mathbf{k}\cdot\mathbf{p}\) band structure calculation
      • Semiconductor Physics
        • Doping in semiconductors: Incomplete ionization
      • Heterostructures
        • Quantum Confined Stark Effect (QCSE)
        • Optical interband absorption in a quantum well including excitonic effects
        • Schottky barrier
      • Transmission
        • Efficient method for the calculation of ballistic quantum transport - The CBR method (2D example)
        • Transmission through a 3D nanowire (3D example)
        • 1D - Quantum Tunneling: Comparison of CBR- and WKB approaches with the exact answer
        • 1D - Quantum Tunneling and Fowler-Nordheim theory
      • Electrolyte
        • Poisson–Boltzmann equation: The Gouy–Chapman solution
        • — DEV — Charge accumulation at the diamond–electrolyte interface
      • Quantum Mechanics
      • Semiconductor Physics
      • Strain and Piezoelectricity
      • Magnetic field
      • Heterostructures
      • k.p
      • T2SL
      • 2DEGs
        • Mobility in two-dimensional electron gases (2DEGs)
      • Optoelectronics
      • Electronics
      • NEGF
      • Electrolyte
      • Graphene
      • Hello World
    • 3.5. Command Line
    • 3.6. Release Notes
      • 2.6.5.b (2024-08-27)
      • 2.6.4.b (2024-08-05)
      • 2.6.1.b (2024-04-02)
      • 2.6.0.b (2024-02-01)
      • 2.5.4.b (2023-07-27)
      • 2.3.8.b (2022-09-29)
      • 2.3.7.b (2022-08-03)
      • EARLIER
  • 4. nextnano.NEGF
    • 4.1. Overview
      • Presentation
      • Software Lineup
      • First steps
    • 4.2. Physical models
      • NEGF formalism
        • Self-consistent solver
        • Convergence
      • Electronic band structure
        • Definition of band offsets
        • Single-band model
        • 2-band model
        • 3-band model
        • 8-band model
        • Output of effective mass in the multiband case
        • Rescaling of \(\mathbf{k} \cdot \mathbf{p}\) parameters (for multiband)
        • Smoothing of the \(\mathbf{k} \cdot \mathbf{p}\) parameters (for multiband)
        • Oscillator strength
      • Green’s functions
        • Steady state assumption
        • Axial energy cut-off
        • Reduced real space basis
        • Energy range of the Green’s functions
        • Relation to physical quantities
        • Coherence length
      • Scattering mechanisms
        • Interface roughness scattering
        • Threading dislocations
        • Acoustic phonon scattering
        • Optical phonon scattering
        • Charged impurity scattering
        • Alloy scattering
        • Electron-electron scattering
      • Electron temperature
        • Subband temperature
        • Effective electron temperature
      • Optical gain/absorption spectrum
        • Gain/absorption calculation from Fermi’s golden rule
        • Gain/absorption calculation from NEGF linear response theory
      • Photon-assisted transport
        • Relation to gain calculation
        • Gain clamping
      • Wall plug efficiency
    • 4.3. Material Database
    • 4.4. Tutorials
      • THz QCLs
        • GaAs/AlGaAs
        • InGaAs/AlGaSb
      • Mid-IR QCLs
        • InGaAs/AlInAs
        • GaAs/AlGaAs
      • — DEV — AlGaAs/GaAs resonant tunneling diode
        • Summary
        • Simulation input
        • Simulation output
      • — DEV — Gain enhancement in interband cascade lasers by carrier-rebalancing under quasi-equilibrium conditions
        • Introduction
        • Models
        • Input file settings
        • Simulation results
        • Prospects
    • 4.5. Keywords
      • Temperature
      • Bias{ }
        • PotentialDrop
      • SweepParameters{ }
        • SweepType
        • Min
        • Max
        • Delta
        • DeltaSmall
        • MinV
        • MaxV
        • DeltaV
        • MinT
        • MaxT
        • DeltaT
        • SchroedingerOnly
      • Equilibrium{ }
        • Broadening
        • Fermi
        • SplitFermi
        • SplitFermiBy
        • FermiElectron
        • FermiHole
        • EnergyBorderElectronHole
      • Crystal{ }
        • CrystalStructure
        • Orientation{ }
        • Orientation{ xAxis{ } }
        • Orientation{ xAxis{ h } }
        • Orientation{ xAxis{ k } }
        • Orientation{ xAxis{ l } }
        • Orientation{ yAxis{ } }
        • Orientation{ zAxis{ } }
        • MaterialSubstrate{ }
        • MaterialSubstrate{ Name }
        • MaterialSubstrate{ AlloyComposition }
        • Strain
        • Piezoelectricity
        • Pyroelectricity
      • Contacts{ }
        • DensityLeft
        • DensityRight
        • FermiPinningLeft
        • FermiPinningRight
        • MaterialLeft
        • MaterialRight
        • Broadening
        • Ballistic
      • Hybrid{ }
        • Broadening
        • SeparationLeft
        • SeparationRight
        • OffsetContact
        • IterPoisson
        • eeNEGF
        • Ballistic
      • Materials{ }
        • Material{ }
        • Material{ Name }
        • Material{ AlloyComposition }
        • Material{ Alias }
        • Material{ EffectiveMassFromKpParameters }
        • Material{ RescaleS }
        • Material{ RescaleSTo }
        • Material{ Overwrite{ } }
        • NumberOfBands
        • UseConductionBandOffset
        • NonParabolicity
        • NonParabolicityRelative
        • InPlaneNonParabolicity
        • TemperatureDependentEightBandDKKParameters
        • ValleyDegeneracy
      • OverwriteMaterialdatabase{ }
        • Material{ }
      • Structure{ }
        • Layer{ }
        • Layer{ Material }
        • Layer{ MaterialLeft }
        • Layer{ MaterialRight }
        • Layer{ Thickness }
        • InterfaceWidth
        • Doping{ }
        • Doping{ DopingType }
        • Doping{ DopingStart }
        • Doping{ DopingEnd }
        • Doping{ DopingSpecification }
        • Doping{ DopingDensity }
        • AnalysisSeparator{ }
        • AnalysisSeparator{ SeparatorPosition }
      • Scattering{ }
        • MaterialForScatteringParameters
        • InterfaceRoughness{ }
        • InterfaceRoughness{ InterfaceWidth }
        • InterfaceRoughness{ AmplitudeInZ }
        • InterfaceRoughness{ InterfaceAutoCorrelationType }
        • InterfaceRoughness{ CorrelationLengthInXY }
        • InterfaceRoughness{ AxialCorrelationLength }
        • ThreadingDislocations{ }
        • ThreadingDislocations{ Density }
        • ThreadingDislocations{ FillingFactor }
        • ThreadingDislocations{ TypePNotN }
        • AcousticPhononScattering
        • AcousticPhononScatteringEnergyMax
        • LOPhononCouplingStrength
        • LOPhononDeformationPotential
        • ScreeningTemperatureType
        • TemperatureOffsetParameter
        • AccuracySelfConsistentElectronTemperature
        • ElectronTemperatureForScreening
        • ImpurityScatteringStrength
        • AlloyScattering
        • AlloyScatteringStrength
        • SeparateScattering
        • MinimizeIFRBroadening
        • ElectronElectronScattering
        • HomogeneousCoulomb
        • CoarseGridCoulomb
        • ElectElectScatteringStrength
        • PhononDamping
        • InterfacesCutOff
        • AugerCoefficient
      • Poisson
        • Poisson
        • IterationPoissonStart
        • FactPoisson
      • LateralDiscretization{ }
        • MaterialForLateralMotion
        • Value
        • OptimizeSampling
        • Dispersion{ }
        • Dispersion{ UnderRelaxationParameter }
        • Dispersion{ PrincipalInplaneK }
      • SimulationParameter{ }
        • CoherenceLengthInPeriods
        • CoherenceLengthInNm
        • CoherenceLengthSelfEnergy
        • BiasForInitialElectronicModes
        • SpatialGridSpacing
        • nLateralPeriodsForBandStructure
        • SmoothingLengthKP
        • ContinuousValenceBand
        • EnergyRangeAxial
        • EnergyRangeAxialValence
        • NumberOfConductionSubbands
        • NumberOfValenceSubbands
        • AssumeIntrinsicNeutrality
        • EnergyRangeLateral
        • EnergyGridSpacing
        • EminShift
        • EmaxShift
        • EnergyReference
        • ConvergenceValueGF
        • ConvergenceMinimum
        • ConvergenceValueCurrent
        • ConvergenceValueNorm
        • NMaxIterations
        • ConvergFactInit
        • ConvergFactMin
        • ConvergFactMax
        • ExitLoopIfNoConvergAfter
        • PhononConvergence
        • MagneticField
        • NMaxThreads
        • StartFromEquilibrium
        • StartFromPrevious
        • BroadenLevels
      • Output{ }
        • EnergyResolvedPlots
        • EnergyResolvedPlotsMinimumEnergyGridSpacing
        • EnergyResolvedPlotsFullRealSpaceResolutionForCurrent
        • EnergyResolvedGain
        • EnergyResolvedGainForEachPhotonEnergy
        • PlotDispersion
        • InPlaneKResolvedData
        • FLDFormat
        • VTKFormat
        • GnuplotFormat
        • ScaleWaveFunction
        • WavefunctionComponents
        • SXYZBasis
      • Gain{ }
        • GainMethod
        • dEPhoto
        • EphotonMin
        • EphotonMax
        • dEPhotoSelfConsistent
        • EphotonMinSelfConsistent
        • EphotonMaxSelfConsistent
        • NMaxSelfConsistentIterations
        • ConvergenceFactorGainSelfConsistent
        • Vmin
        • Vmax
        • CavityLosses
        • FrontMirrorLosses
        • GainClamping
        • OverlapFactor
        • Threshold
        • RefineThreshold
        • Gauge
        • SelfConsistentBoundary
        • FermiGoldenRule{ }
        • FermiGoldenRule{ Linewidth }
        • FermiGoldenRule{ LinewidthMin }
        • FermiGoldenRule{ EphotonMin }
        • FermiGoldenRule{ EphotonMax }
        • Polarization{}
        • Polarization{ Re }
        • Polarization{ Im }
      • SurfaceRoughness{ }
        • Amplitude
        • CorrelationLength
      • EMfield{ }
        • EMmode{ }
        • EMmode{ PhotonEnergy }
        • EMmode{ ElectricField }
        • EMmode{ Intensity }
        • EMmode{ Polarization{ } }
        • EMmode{ Polarization{ Re } }
        • EMmode{ Polarization{ Im } }
    • 4.6. Input Syntax
    • 4.7. Simulation Output
      • Overview
      • Init_Electron_Modes folder
    • 4.8. Command Line
    • 4.9. Release Notes
      • Upcoming changes
      • 2024-09-16
      • 2024-07-25
      • 2024-06-21
      • 2024-05-23
      • 2024-03-14
      • 2023-12-01
      • 2023-05-25
      • 2023-02-22
    • 4.10. FAQs
      • Features and Functionalities
        • Can you recommend some reading material on the background of the NEGF method?
        • What is the difference between the “RealSpaceModes” and “EnergyEigenstates” in the output folder?
        • What are the meanings of “Check normalization of spectral function = …” and “Check normalization of lesser Green’s function = …” in the log file?
      • Error Messages
        • nextnano.NEGF exit code: -…
      • Problems and Limitations
        • How much memory do I need?
        • My results do not agree with experiment.
        • Why does the current density vary at different places? Current does not seem to be conserved.
        • In the gain spectra, the energy grid is not as expected from the input nn.NEGF_Gain{ dEPhot }/nn.NEGF_Gain{ dEPhotSelfConsistent }.
    • 4.11. Release Notes (Classic)
      • 2024-01-17
      • 2022-06-13
      • 2022-04-29
      • 2022-03-14
    • 4.12. FAQs (Classic)
      • Features and Functionalities
        • Can you recommend some reading material on the background of the NEGF method?
        • What is the difference between the “RealSpaceModes” and “Wannier-Stark_levels”?
        • What are the meanings of “Check G lesser = …” and “Check spectral function = …” in the log file?
      • Error Messages
        • Licensing.dll not loaded
      • Problems and Limitations
        • How much memory do I need?
        • My results do not agree with experiment.
        • Why does the current density vary at different places? Current does not seem to be conserved.
        • In the gain spectra, the energy grid is not as expected from the input nn.NEGF_Gain{ dEPhot }/nn.NEGF_Gain{ dEPhotSelfConsistent }.
        • The simulation results contain the Gain folder but it is empty.
  • 5. nextnano.MSB
    • 5.1. Overview
    • 5.2. Command line arguments
    • 5.3. Input file syntax
      • Input file
      • General syntax
    • 5.4. Material database
      • Elements and binary compounds
        • ConductionBandOffset
        • ValenceBandOffset
        • BandGap
        • BandGapAlpha
        • BandGapBeta
        • ElectronMass
        • EpsStatic
        • EpsOptic
        • LOPhononEnergy
        • LOPhononWidth
        • DeformationPotential
        • MaterialDensity
        • VelocityOfSound
        • AcousticPhononEnergy
        • Lattice_a
        • Elastic_c11
        • Elastic_c12
        • Elastic_c44
        • Piezo_e14
      • Ternary compounds
      • Quaternary compounds
    • 5.5. Simulation output
      • Input
        • Material parameters
        • Input parameters
      • Output
        • Energy profile
        • Eigenstates
        • CarrierDensity
        • DOS
        • Probes
        • Gain
        • Gain-voltage characteristics
        • Transmission
        • Current density
        • Current-voltage characteristics (I-V curve)
    • 5.6. Log file
    • 5.7. Tutorials
      • Transmission coefficient of a double barrier structure
      • Ballistic current calculation of a GaAs nin resistor
        • Example 1
        • Example 2
      • Resonant tunneling diode (RTD)
      • Quantum Well
      • AlGaAs/GaAs THz QCL
  • 6. nextnanopy
    • 6.1. Overview
      • What is nextnanopy?
      • How do I install it?
      • Where to start?
    • 6.2. Tutorials
      • Basic Tutorials
      • Data Visualization
    • 6.3. Release Notes
  • 7. nextnanoevo
    • 7.1. Overview
      • About
      • Purpose
      • Requirements
      • Installation
      • License activation
      • Config setup
    • 7.2. Definitions
      • nextnanoevo.IO
      • Metric
    • 7.3. Tutorials
      • PyGMO
        • Maximizing Envelope Overlaps for a Given Transition Energy
        • Optimization of Mid-IR Quantum Cascade Laser Gain
      • SciPy
        • Optimizing well width for specific target transition energy in an infinite quantum well
        • Optimization of a 2DEG structure

Cloud Computing

  • HTCondor
    • HTCondor on nextnanomat
    • Recommended Installation Process
      • Summary of settings (Example)
      • Config file
      • Configuring a pool without a domain
    • Submitting jobs to HTCondor pool with nextnanomat
    • Useful HTCondor commands for the Command Prompt
    • HTCondor Pool - Managing Slots
      • Dynamic slots
    • Machine states
    • Machine activities
    • Configuration options for the Central Manager computer
    • FAQ
    • Problems with HTCondor
      • Error: communication error
      • Error: condor_store_cred add failed with Operation failed. Make sure your ALLOW_WRITE setting include this host.
      • Error? Check the Log files
    • Known bugs
    • Run your custom executable on HTCondor with nextnanomat
      • Input file identifier
      • Settings for Hello World (HW)
      • Settings for Quantum ESPRESSO (QE)
      • Settings for ABINIT
        • Notes

Support

  • Support Ticket System
    • How to get the fastest support possible?
    • Channels
      • Help Center (recommended)
      • Widget
      • Email
  • Preparing Support Request
    • nextnano simulation does not start
      • Possible error sources
      • Files to be included in support request
    • nextnano simulation does not finish (errors in log file)
    • nextnanomat GUI does not start
    • nextnanomat GUI prompts error or exception message
  • Frequently Asked Questions (FAQ)
    • FAQ - General
      • Copyright Statement
      • Are there any video tutorials available?
      • Hardware requirements for nextnano? I want to buy a new computer. What shall I buy?
      • How shall I cite the nextnano software in publications?
    • FAQ - Licensing
      • Which types of licenses exist?
      • How many people can use the software simultaneously?
      • Which license do I need for Cluster computing?
      • Is there a possibility to evaluate the nextnano software before purchasing?
      • I remember there have been .txt licenses before, what happened to them?
      • License activation
        • I do not have a license (key).
        • I already purchased a license.
        • Can I activate my license without using nextnanomat?
      • Errors and Exceptions

References

  • Books
  • Theses
  • Journal Papers

Old Sites

  • Old Sites
    • Downloads
    • Release Notes
      • nextnanomat — release notes
      • Release notes of nextnano++
      • Release notes of nextnano³
      • nextnano.NEGF — release notes
      • nextnano.NEGF_classic — release notes
    • Applications
    • run{ }
    • strain{ }
    • currents{}
    • mobility_model
    • structure{ } - outputs
    • structure{ region{} } - Repeating regions
    • structure{ region{} } - boundary conditions
    • structure{ region{ doping{ } } }
    • Standard & Evaluation
    • About the nextnano Software
    • — EDU — Orbitals of the Hydrogen Atom
    • FAQ - nextnanomat
    • FAQ - nextnano++ and nextnano³
    • FAQ - Errors and Exceptions
nextnano Documentation
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  • 4. nextnano.NEGF »
  • 4.12. FAQs (Classic)
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4.12. FAQs (Classic)¶

  • Features and Functionalities
    • Can you recommend some reading material on the background of the NEGF method?
    • What is the difference between the “RealSpaceModes” and “Wannier-Stark_levels”?
    • What are the meanings of “Check G lesser = …” and “Check spectral function = …” in the log file?
  • Error Messages
    • Licensing.dll not loaded
  • Problems and Limitations
    • How much memory do I need?
    • My results do not agree with experiment.
    • Why does the current density vary at different places? Current does not seem to be conserved.
    • In the gain spectra, the energy grid is not as expected from the input nn.NEGF_Gain{ dEPhot }/nn.NEGF_Gain{ dEPhotSelfConsistent }.
    • The simulation results contain the Gain folder but it is empty.

Last update: 30/10/2024

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