Section TRANSPORT

• Specifies the parameters for transport, sets parameters for the OMEN code, see also http://www.nano-tcad.ethz.ch/

• Section path: CP2K_INPUT / FORCE_EVAL / DFT / TRANSPORT

• This section cannot be repeated.

• This section cites the following reference: [Bruck2014]

• Subsections

  • BEYN
  • CONTACT
  • PEXSI
  • PRINT

• Keywords

  • COLZERO_THRESHOLD
  • CONTACT_FILLING
  • CSR_SCREENING
  • CUTOUT
  • DENSITY_MIXING
  • ENERGY_INTERVAL
  • EPS_DECAY
  • EPS_EIGVAL_DEGEN
  • EPS_FERMI
  • EPS_LIMIT
  • EPS_LIMIT_CC
  • EPS_MU
  • EPS_SINGULARITY_CURVATURES
  • GPUS_PER_POINT
  • INJECTION_METHOD
  • LINEAR_SOLVER
  • MATRIX_INVERSION_METHOD
  • MIN_INTERVAL
  • NUM_INTERVAL
  • NUM_POLE
  • N_KPOINTS
  • N_POINTS_INV
  • OBC_EQUILIBRIUM
  • QT_FORMALISM
  • REAL_AXIS_INTEGRATION_METHOD
  • TASKS_PER_ENERGY_POINT
  • TASKS_PER_POLE
  • TEMPERATURE
  • TRANSPORT_METHOD

• Keyword descriptions

  COLZERO_THRESHOLD
  	COLZERO_THRESHOLD {Real}
  	The smallest number that is not zero in the full diagonalization part.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-012

  CONTACT_FILLING
  	CONTACT_FILLING {Keyword}
  	Determination of the contact Fermi levels. Note that this keyword only works when the TRANSPORT_METHOD is specified as TRANSPORT.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: BAND_STRUCTURE
  	List of valid keywords: BAND_STRUCTURE Determine the Fermi levels from the band structure. DOS Determine the Fermi levels from the density of states.

  CSR_SCREENING
  	CSR_SCREENING {Logical}
  	Whether distance screening should be applied to improve sparsity of CSR matrices.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .TRUE.

  CUTOUT
  	CUTOUT {Integer} {Integer}
  	The number of atoms at the beginning and the end of the structure where the density should not be changed.
  	This keyword cannot be repeated and it expects precisely 2 integers.
  	Default values: 0 0

  DENSITY_MIXING
  	DENSITY_MIXING {Real}
  	Mixing parameter for a density mixing in OMEN.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E+000

  ENERGY_INTERVAL
  	ENERGY_INTERVAL {Real}
  	Distance between energy points in eV.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-003

  EPS_DECAY
  	EPS_DECAY {Real}
  	The smallest imaginary part that a decaying eigenvalue may have not to be considered as propagating.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-004

  EPS_EIGVAL_DEGEN
  	EPS_EIGVAL_DEGEN {Real}
  	Filter for degenerate bands in the injection vector.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-006

  EPS_FERMI
  	EPS_FERMI {Real}
  	Cutoff for the tail of the Fermi function.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000

  EPS_LIMIT
  	EPS_LIMIT {Real}
  	The smallest eigenvalue that is kept.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-004

  EPS_LIMIT_CC
  	EPS_LIMIT_CC {Real}
  	The smallest eigenvalue that is kept on the complex contour.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-006

  EPS_MU
  	EPS_MU {Real}
  	Accuracy to which the Fermi level should be determined.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-006

  EPS_SINGULARITY_CURVATURES
  	EPS_SINGULARITY_CURVATURES {Real}
  	Filter for degenerate bands in the bandstructure.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-012

  GPUS_PER_POINT
  	GPUS_PER_POINT {Integer}
  	Number of GPUs per energy point for SplitSolve. Needs to be a power of two
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 2

  INJECTION_METHOD
  	INJECTION_METHOD {Keyword}
  	Method to solve the eigenvalue problem for the open boundary conditions.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: BEYN
  	List of valid keywords: BEYN Beyn eigenvalue solver. EVP Full eigenvalue solver.

  LINEAR_SOLVER
  	LINEAR_SOLVER {Keyword}
  	Preferred solver for solving the linear system of equations.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: FULL
  	List of valid keywords: BANDED Without description, yet. FULL Without description, yet. MUMPS Without description, yet. PARDISO Without description, yet. SPLITSOLVE Without description, yet. SUPERLU Without description, yet. UMFPACK Without description, yet.

  MATRIX_INVERSION_METHOD
  	MATRIX_INVERSION_METHOD {Keyword}
  	Preferred matrix inversion method.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: FULL
  	List of valid keywords: FULL Without description, yet. PARDISO Without description, yet. PEXSI Without description, yet. RGF Without description, yet.

  MIN_INTERVAL
  	MIN_INTERVAL {Real}
  	Smallest enery distance in energy vector.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-004

  NUM_INTERVAL
  	NUM_INTERVAL {Integer}
  	Max number of energy points per small interval.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 10

  NUM_POLE
  	NUM_POLE {Integer}
  	The number of terms in the PEXSI's pole expansion method.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 64

  N_KPOINTS
  	N_KPOINTS {Integer}
  	The number of k points for determination of the singularities.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 64

  N_POINTS_INV
  	N_POINTS_INV {Integer}
  	Number of integration points for the sigma solver on the complex contour.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 64

  OBC_EQUILIBRIUM
  	OBC_EQUILIBRIUM {Logical}
  	Compute the equilibrium density with open boundary conditions.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  QT_FORMALISM
  	QT_FORMALISM {Keyword}
  	Preferred quantum transport formalism to compute the current and density.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: QTBM
  	List of valid keywords: NEGF The non-equilibrium Green's function formalism. QTBM The quantum transmitting boundary method / wave-function formalism.

  REAL_AXIS_INTEGRATION_METHOD
  	REAL_AXIS_INTEGRATION_METHOD {Keyword}
  	Integration method for the real axis.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: GAUSS_CHEBYSHEV
  	List of valid keywords: GAUSS_CHEBYSHEV Gauss-Chebyshev integration between singularity points. READ Read integration points from a file (named E.dat). TRAPEZOIDAL_RULE Trapezoidal rule on the total range.

  TASKS_PER_ENERGY_POINT
  	TASKS_PER_ENERGY_POINT {Integer}
  	Number of tasks per energy point. The value should be a divisor of the total number of MPI ranks.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 1

  TASKS_PER_POLE
  	TASKS_PER_POLE {Integer}
  	Number of tasks per pole in the pole expansion method. The value should be a divisor of the total number of MPI ranks.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 1

  TEMPERATURE
  	TEMPERATURE {Real}
  	Temperature.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 3.00000000E+002
  	Default unit: [K]

  TRANSPORT_METHOD
  	TRANSPORT_METHOD {Keyword}
  	Preferred method for transport calculations.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: TRANSPORT
  	List of valid keywords: LOCAL_SCF CP2K valence Hamiltonian + OMEN self-consistent calculations on conduction electrons TRANSMISSION self-consistent transmission calculations without applied bias voltage TRANSPORT self-consistent CP2K and OMEN transport calculations