Section NEGF

• Parameters which control quantum transport calculation based on Non-Equilibrium Green's Function method.

• Section path: CP2K_INPUT / NEGF

• This section cannot be repeated.

• This section cites the following references: [Papior2017] [Rocha2006b]

• Subsections

  • CONTACT
  • MIXING
  • PRINT
  • SCATTERING_REGION

• 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
  	DELTA_NPOLES {Integer}
  	Number of poles of Fermi function to consider.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 4

  DISABLE_CACHE
  	DISABLE_CACHE {Logical}
  	Do not keep contact self-energy matrices for future reuse
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  ENERGY_LBOUND
  	ENERGY_LBOUND {Real}
  	Lower bound energy of the conductance band.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: -5.00000000E+000
  	Default unit: [hartree]

  EPS_DENSITY
  	EPS_DENSITY {Real}
  	Target accuracy for electronic density.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-005

  EPS_GEO
  	EPS_GEO {Real}
  	Accuracy in mapping atoms between different force environments.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 5.29177209E-007
  	Default unit: [angstrom]

  EPS_GREEN
  	EPS_GREEN {Real}
  	Target accuracy for surface Green's functions.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-005

  EPS_SCF
  	EPS_SCF {Real}
  	Target accuracy for SCF convergence.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-005

  ETA
  	ETA {Real}
  	Infinitesimal offset from the real axis.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-005
  	Default unit: [hartree]

  GAMMA_KT
  	GAMMA_KT {Integer}
  	Offset from the axis (in terms of k*T) where poles of the Fermi function reside.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 20

  HOMO_LUMO_GAP
  	HOMO_LUMO_GAP {Real}
  	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.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 2.00000000E-001
  	Default unit: [hartree]

  INTEGRATION_MAX_POINTS
  	INTEGRATION_MAX_POINTS {Integer}
  	Maximal number of grid point for adaptive numerical integration.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 512

  INTEGRATION_METHOD
  	INTEGRATION_METHOD {Keyword}
  	Method to integrate Green's functions along a closed-circuit contour.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: CLENSHAW-CURTIS
  	List of valid keywords: CLENSHAW-CURTIS Adaptive Clenshaw-Curtis quadrature method. Requires FFTW3 library. SIMPSON Adaptive Simpson method. Works without FFTW3.

  INTEGRATION_MIN_POINTS
  	INTEGRATION_MIN_POINTS {Integer}
  	Initial (minimal) number of grid point for adaptive numerical integration.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 16

  MAX_SCF
  	MAX_SCF {Integer}
  	Maximum number of SCF iterations to be performed.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 30

  NPROC_POINT
  	NPROC_POINT {Integer}
  	Number of MPI processes to be used per energy point. Default is to use all processors (0).
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 0

  V_SHIFT
  	V_SHIFT {Real}
  	Initial value of the Hartree potential shift
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000
  	Default unit: [hartree]

  V_SHIFT_MAX_ITERS
  	V_SHIFT_MAX_ITERS {Integer}
  	Maximal number of iteration to determine the optimal shift in Hartree potential.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 30

  V_SHIFT_OFFSET
  	V_SHIFT_OFFSET {Real}
  	Initial offset to determine the optimal shift in Hartree potential.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-001