NEGF

References: Rocha2006b, Papior2017

Parameters which control quantum transport calculation based on Non-Equilibrium Green Function method. [Edit on GitHub]

Subsections

• CONTACT
• MIXING
• PRINT
• SCATTERING_REGION
• SCF

Keywords

• DELTA_NPOLES

• DISABLE_CACHE

• ENERGY_LBOUND

• EPS_DENSITY

• EPS_GEO

• EPS_GREEN

• EPS_SCF

• ETA

• GAMMA_KT

• HOMO_LUMO_GAP

• INTEGRATION_MAX_POINTS

• INTEGRATION_METHOD

• INTEGRATION_MIN_POINTS

• MAX_SCF

• NPROC_POINT

• V_SHIFT

• V_SHIFT_MAX_ITERS

• V_SHIFT_OFFSET

Keyword descriptions

DELTA_NPOLES

Type: integer
Default: 4

Description: Number of poles of Fermi function to consider.

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DISABLE_CACHE

Type: logical
Default: F
Lone keyword: T

Description: Do not keep contact self-energy matrices for future reuse

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ENERGY_LBOUND

Type: real
Default: -5.00000000E+000 [hartree]

Description: Lower bound energy of the conductance band.

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EPS_DENSITY

Type: real
Default: 1.00000000E-005

Description: Target accuracy for electronic density.

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EPS_GEO

Type: real
Default: 5.29177209E-007 [angstrom]

Description: Accuracy in mapping atoms between different force environments.

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EPS_GREEN

Type: real
Default: 1.00000000E-005

Description: Target accuracy for surface Green’s functions.

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EPS_SCF

Type: real
Default: 1.00000000E-005

Description: Target accuracy for SCF convergence.

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ETA

Type: real
Default: 1.00000000E-005 [hartree]

Description: Infinitesimal offset from the real axis.

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GAMMA_KT

Type: integer
Default: 20

Description: Offset from the axis (in terms of k*T) where poles of the Fermi function reside.

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HOMO_LUMO_GAP

Type: real
Default: 2.00000000E-001 [hartree]

Description: The gap between the HOMO and some fictitious LUMO. This option is used as an initial offset to determine the actual Fermi level of bulk contacts. It does not need to be exact HOMO-LUMO gap, just some value to start with.

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INTEGRATION_MAX_POINTS

Type: integer
Default: 512

Description: Maximal number of grid point for adaptive numerical integration.

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INTEGRATION_METHOD

Type: enum
Default: CLENSHAW-CURTIS

Description: Method to integrate Green’s functions along a closed-circuit contour.

Valid values:

• CLENSHAW-CURTIS Adaptive Clenshaw-Curtis quadrature method. Requires FFTW3 library.

• SIMPSON Adaptive Simpson method. Works without FFTW3.

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INTEGRATION_MIN_POINTS

Type: integer
Default: 16

Description: Initial (minimal) number of grid point for adaptive numerical integration.

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MAX_SCF

Type: integer
Default: 30

Description: Maximum number of SCF iterations to be performed.

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NPROC_POINT

Type: integer
Default: 0

Description: Number of MPI processes to be used per energy point. Default is to use all processors (0).

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V_SHIFT

Type: real
Default: 0.00000000E+000 [hartree]

Description: Initial value of the Hartree potential shift

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V_SHIFT_MAX_ITERS

Type: integer
Default: 30

Description: Maximal number of iteration to determine the optimal shift in Hartree potential.

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V_SHIFT_OFFSET

Type: real
Default: 1.00000000E-001

Description: Initial offset to determine the optimal shift in Hartree potential.

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