TRANSPORT

References: Bruck2014

Specifies the parameters for transport, sets parameters for the OMEN code, see also https://nano-tcad.ee.ethz.ch. [Edit on GitHub]

Subsections

Keywords

Keyword descriptions

COLZERO_THRESHOLD

Type: real
Default: 1.00000000E-012
Usage: COLZERO_THRESHOLD

Description: The smallest number that is not zero in the full diagonalization part.

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CONTACT_FILLING

Type: enum
Default: BAND_STRUCTURE

Description: Determination of the contact Fermi levels. Note that this keyword only works when the TRANSPORT_METHOD is specified as TRANSPORT.

Valid values:

  • BAND_STRUCTURE Determine the Fermi levels from the band structure.

  • DOS Determine the Fermi levels from the density of states.

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CSR_SCREENING

Type: logical
Default: T
Lone keyword: T

Description: Whether distance screening should be applied to improve sparsity of CSR matrices.

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CUTOUT

Type: integer[2]
Default: 0 0
Usage: CUTOUT

Description: The number of atoms at the beginning and the end of the structure where the density should not be changed.

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DENSITY_MIXING

Type: real
Default: 1.00000000E+000
Usage: DENSITY_MIXING

Description: Mixing parameter for a density mixing in OMEN.

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ENERGY_INTERVAL

Type: real
Default: 1.00000000E-003
Usage: ENERGY_INTERVAL

Description: Distance between energy points in eV.

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EPS_DECAY

Type: real
Default: 1.00000000E-004
Usage: EPS_DECAY

Description: The smallest imaginary part that a decaying eigenvalue may have not to be considered as propagating.

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EPS_EIGVAL_DEGEN

Type: real
Default: 1.00000000E-006
Usage: EPS_EIGVAL_DEGEN

Description: Filter for degenerate bands in the injection vector.

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EPS_FERMI

Type: real
Default: 0.00000000E+000
Usage: EPS_FERMI

Description: Cutoff for the tail of the Fermi function.

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EPS_LIMIT

Type: real
Default: 1.00000000E-004
Usage: EPS_LIMIT

Description: The smallest eigenvalue that is kept.

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EPS_LIMIT_CC

Type: real
Default: 1.00000000E-006
Usage: EPS_LIMIT_CC

Description: The smallest eigenvalue that is kept on the complex contour.

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EPS_MU

Type: real
Default: 1.00000000E-006
Usage: EPS_MU

Description: Accuracy to which the Fermi level should be determined.

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EPS_SINGULARITY_CURVATURES

Type: real
Default: 1.00000000E-012
Usage: EPS_SINGULARITY_CURVATURES

Description: Filter for degenerate bands in the bandstructure.

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GPUS_PER_POINT

Type: integer
Default: 2
Usage: GPUS_PER_POINT

Description: Number of GPUs per energy point for SplitSolve. Needs to be a power of two

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INJECTION_METHOD

Type: enum
Default: BEYN
Usage: INJECTION_METHOD

Description: Method to solve the eigenvalue problem for the open boundary conditions.

Valid values:

  • EVP Full eigenvalue solver.

  • BEYN Beyn eigenvalue solver.

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LINEAR_SOLVER

Type: enum
Default: FULL
Usage: LINEAR_SOLVER

Description: Preferred solver for solving the linear system of equations.

Valid values:

  • SPLITSOLVE

  • SUPERLU

  • MUMPS

  • FULL

  • BANDED

  • PARDISO

  • UMFPACK

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MATRIX_INVERSION_METHOD

Type: enum
Default: FULL
Usage: MATRIX_INVERSION_METHOD

Description: Preferred matrix inversion method.

Valid values:

  • FULL

  • PEXSI

  • PARDISO

  • RGF

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MIN_INTERVAL

Type: real
Default: 1.00000000E-004
Usage: MIN_INTERVAL

Description: Smallest enery distance in energy vector.

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NUM_INTERVAL

Type: integer
Default: 10
Usage: NUM_INTERVAL

Description: Max number of energy points per small interval.

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NUM_POLE

Type: integer
Default: 64
Usage: NUM_POLE

Description: The number of terms in the PEXSI’s pole expansion method.

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N_KPOINTS

Type: integer
Default: 64
Usage: N_KPOINTS

Description: The number of k points for determination of the singularities.

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N_POINTS_INV

Type: integer
Default: 64
Usage: N_POINTS_INV

Description: Number of integration points for the sigma solver on the complex contour.

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OBC_EQUILIBRIUM

Type: logical
Default: F
Lone keyword: T

Description: Compute the equilibrium density with open boundary conditions.

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QT_FORMALISM

Type: enum
Default: QTBM
Usage: QT_FORMALISM

Description: Preferred quantum transport formalism to compute the current and density.

Valid values:

  • NEGF The non-equilibrium Green’s function formalism.

  • QTBM The quantum transmitting boundary method / wave-function formalism.

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REAL_AXIS_INTEGRATION_METHOD

Type: enum
Default: GAUSS_CHEBYSHEV
Usage: REAL_AXIS_INTEGRATION_METHOD

Description: Integration method for the real axis.

Valid values:

  • GAUSS_CHEBYSHEV Gauss-Chebyshev integration between singularity points.

  • TRAPEZOIDAL_RULE Trapezoidal rule on the total range.

  • READ Read integration points from a file (named E.dat).

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TASKS_PER_ENERGY_POINT

Type: integer
Default: 1
Usage: TASKS_PER_ENERGY_POINT

Description: Number of tasks per energy point. The value should be a divisor of the total number of MPI ranks.

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TASKS_PER_POLE

Type: integer
Default: 1
Usage: TASKS_PER_POLE

Description: Number of tasks per pole in the pole expansion method. The value should be a divisor of the total number of MPI ranks.

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TEMPERATURE

Type: real
Default: 3.00000000E+002 [K]
Usage: TEMPERATURE [K] 300.0

Description: Temperature.

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TRANSPORT_METHOD

Type: enum
Default: TRANSPORT
Usage: TRANSPORT_METHOD

Description: Preferred method for transport calculations.

Valid values:

  • TRANSPORT self-consistent CP2K and OMEN transport calculations

  • LOCAL_SCF CP2K valence Hamiltonian + OMEN self-consistent calculations on conduction electrons

  • TRANSMISSION self-consistent transmission calculations without applied bias voltage

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