 |
Core NanoLanguage elements |  |
|---|---|---|
| energyContourIntegralParameters | TwoProbeConfiguration |
| |
Core NanoLanguage elements | |
|---|---|---|
| energyContourIntegralParameters | TwoProbeConfiguration |
GatedTwoProbeMethod — Extends the TwoProbeMethod class to simulate a two-probe system with a gate electrode.
The GatedTwoProbeMethod class is an extension
of the TwoProbeMethod class, and is used for
the parameters that control the calculation of a two-probe system where the effect
of a gate voltage is simulated. The returned object is used as an input parameter to
executeSelfConsistentCalculation() which
performs the actual self-consistent calculation. Alternatively, the
apply() method of the method object itself (see below) can
be used.
List of arguments
A TwoProbeMethod object.
Default:
None
The simulated voltage on the electrostatic gate.
Default: 0.0*Volt
The number of surface atoms at each end of the central region.
By surface atoms we here refer to the atoms that are not affected by the gate voltage.
Should be given as a tuple, e.g. (5,10). In this specific case, the first 5 atoms
and the 10 last atoms in the scattering_region_elements list, are
not affected by the gate voltage.
Default: (0,0).
This corresponds a gate voltage applied to all the atoms in the scattering
region.
Create a three-probe object based on the GatedTwoProbeMethod:
from ATK.TwoProbe import * ... configuration = TwoProbeConfiguration(...) two_probe_method = TwoProbeMethod(...) three_probe_method = GatedTwoProbeMethod( two_probe_method = two_probe_method gate_voltage = 5*Volt ) scf = executeSelfConsistentCalculation( configuration, method=three_probe_method )
It is also possible to execute the self-consistent calculation by using the
apply() method of the GatedTwoProbeMethod class. For more details, see
the KohnShamMethod class.
The gate electrode is not included as a physical electrode in ATK, and, consequently, no current can run from the source or drain electrode to the gate electrode. In the current implementation, the electrostatic effect of the gate electrode is simulated by simply shifting the scattering region part of the Hamiltonian with the gate voltage (converted into an electrostatic potential energy). This corresponds to assuming that the gate electrode induces an external potential localized in the scattering region. For metallic electrodes this will usually be a reasonable approximation.
The conversion of the gate voltage used in a physical system to the gate voltage specified in ATK potential energy is not trivial, as it would require a specification of the geometry used in the physical system and a solution of the Poisson equation that relates the electrostatic potential in the scattering region to the applied gate voltage.
| |
|
|
| energyContourIntegralParameters |
|
TwoProbeConfiguration |