SweepParameters{ }¶

Calling sequence

SweepParameters{ ... }

Functionality

Specifies voltage, temperature, or electric-field sweep in the simulation. The C++ version of nextnano.NEGF (see Release Notes) supports voltage and electric-field sweep.

Dependencies

For a single simulation, Temperature and Bias{ } must be specified.

Dependencies

All Min, Max must be defined if Delta is defined.
All MinV, MaxV must be defined if DeltaV is defined.
All MinT, MaxT must be defined if DeltaT is defined.
None of MinV, MinT are allowed to be defined if Min is defined.
None of MaxV, MaxT are allowed to be defined if Max is defined.

Example

SweepParameters{
    SweepType = Single
}

SweepParameters{
    SweepType = Voltage
    Min = 200
    Max = 500
    Delta = 50
}

SweepParameters{
    SweepType = Efield
    Min = 1e6
    Max = 8e6
    Delta = 1e6
    DeltaSmall = 0.1e6
}

Note

The C# version of nextnano.NEGF supports voltage, temperature, and combined temperature-voltage sweep.

<SweepParameters>
    <SweepType>Voltage</SweepType>  <!-- "Voltage" or "Temperature" -->
    <Min>20</Min>
    <Max>500</Max>
    <Delta>20</Delta>
</SweepParameters>

In this case, we define the start and end of the voltage or temperature as well as its increment. The units are [mV/period] for the voltage sweep and [K] for the temperature sweep.

<SweepParameters>
    <SweepType>Temperature-Voltage</SweepType>
    <MinV>50</MinV>
    <MaxV>60</MaxV>
    <DeltaV>2</DeltaV>
    <MinT>25</MinT>
    <MaxT>300</MaxT>
    <DeltaT>25</DeltaT>

    <Threads>12</Threads>
</SweepParameters>

In this case, the simulation can be parallelized. Threads defines the number of parallel threads (typically the number of CPU cores available). Within each parallel temperature sweep, a standard voltage sweep is performed.

The following keywords are available within this group:

SweepType¶

Calling sequence

SweepParameters{ SweepType }

Properties

type: \(\mathrm{character\;string}\)
Single, Voltage, or Efield (C++ version, see Release Notes)
Voltage, Temperature, or Temperature-Voltage (C# version, see Release Notes (Classic))

Functionality

This defines the start and end of the voltage or temperature as well as its increment.

Note

The temperature-voltage sweep is available in the C# version and will be implemented in the C++ version as well. Here, the value of the last calculated bias value below threshold bias is used as a starting point of the following bias sweep at the next temperature.

Min¶

Calling sequence

SweepParameters{ Min }

Properties

type: \(\mathrm{real\;number}\)

Functionality

Sets the minimum value of the sweep range.

Max¶

Calling sequence

SweepParameters{ Max }

Properties

type: \(\mathrm{real\;number}\)

Functionality

Sets the maximum value of the sweep range.

Delta¶

Calling sequence

SweepParameters{ Delta }

Properties

type: \(\mathrm{real\;number}\)
values: [0.0, ...)

Functionality

Specifies the interval of the sweep values.

DeltaSmall¶

Calling sequence

SweepParameters{ DeltaSmall }

Properties

type: \(\mathrm{real\;number}\)
values: [0.0, ...)

Functionality

Specifies alternating electric-field intervals. This option can be used to improve the accuracy of capacitance-voltage curves.

MinV¶

Calling sequence

SweepParameters{ MinV }

Properties

type: \(\mathrm{real\;number}\)
unit: \(\mathrm{mV}\)

Functionality

Sets the minimum value of the voltage sweep range.

MaxV¶

Calling sequence

SweepParameters{ MaxV }

Properties

type: \(\mathrm{real\;number}\)
unit: \(\mathrm{mV}\)

Functionality

Sets the maximum value of the voltage sweep range.

DeltaV¶

Calling sequence

SweepParameters{ DeltaV }

Properties

type: \(\mathrm{real\;number}\)
values: [0.0, ...)
unit: \(\mathrm{mV}\)

Functionality

Specifies the interval of the voltage sweep values.

MinT¶

Calling sequence

SweepParameters{ MinT }

Properties

type: \(\mathrm{real\;number}\)
values: [0.0, ...)
unit: \(\mathrm{K}\)

Functionality

Sets the minimum value of the sweep range of the lattice temperature.

MaxT¶

Calling sequence

SweepParameters{ MaxT }

Properties

type: \(\mathrm{real\;number}\)
values: [0.0, ...)
unit: \(\mathrm{K}\)

Functionality

Sets the maximum value of the sweep range of the lattice temperature.

DeltaT¶

Calling sequence

SweepParameters{ DeltaT }

Properties

type: \(\mathrm{real\;number}\)
values: [0.0, ...)
unit: \(\mathrm{K}\)

Functionality

Specifies the interval of the lattice temperature values.

SchroedingerOnly¶

Calling sequence

SweepParameters{ SchroedingerOnly }

Properties

choices: yes; no
default: no

Functionality

If yes, the program exits once it has diagonalized the Hamiltonian and calculated the NEGF basis. This option can be useful to inspect and tune the inputs about the heterostructure before actually simulating non-equilibrium quantum transport.

Example

SweepParameters{
    SchroedingerOnly = yes
}

Last update: 19/11/2024