DFT+U

Name ACBN0IntersiteCutoff
Section Hamiltonian::DFT+U
Type float

The cutoff radius defining the maximal intersite distance considered. Only available with ACBN0 functional with intersite interaction.

Name ACBN0IntersiteInteraction
Section Hamiltonian::DFT+U
Type logical
Default no

If set to yes, Octopus will determine the effective intersite interaction V Only available with ACBN0 functional. It is strongly recommended to set AOLoewdin=yes when using the option.

Name ACBN0RotationallyInvariant
Section Hamiltonian::DFT+U
Type logical

If set to yes, Octopus will use for U and J a formula which is rotationally invariant. This is different from the original formula for U and J. This is activated by default, except in the case of spinors, as this is not yet implemented in this case.

Name ACBN0Screening
Section Hamiltonian::DFT+U
Type float
Default 1.0

If set to 0, no screening will be included in the ACBN0 functional, and the U will be estimated from bare Hartree-Fock. If set to 1 (default), the full screening of the U, as defined in the ACBN0 functional, is used.

Name DFTUBasisFromStates
Section Hamiltonian::DFT+U
Type logical
Default no

If set to yes, Octopus will construct the localized basis from user-defined states. The states are taken at the Gamma point (or the first k-point of the states in the restart_proj folder. The states are defined via the block DFTUBasisStates

Name DFTUBasisStates
Section Hamiltonian::DFT+U
Type block
Default none

This block starts by a line containing a single integer describing the number of orbital sets. One orbital set is a group of orbitals on which one adds a Hubbard U. Each following line of this block contains the index of a state to be used to construct the localized basis, followed by the index of the corresponding orbital set. See DFTUBasisFromStates for details.

Name DFTUDoubleCounting
Section Hamiltonian::DFT+U
Type integer
Default dft_u_fll

This variable selects which DFT+U double counting term is used.

Options:

• dft_u_fll:
  (Default) The Fully Localized Limit (FLL)
  
• dft_u_amf:
  (Experimental) Around mean field double counting, as defined in PRB 44, 943 (1991) and PRB 49, 14211 (1994).
  

Name DFTUPoissonSolver
Section Hamiltonian::DFT+U
Type integer

This variable selects which Poisson solver is used to compute the Coulomb integrals over a submesh. These are non-periodic Poisson solvers. The FFT Poisson solver with spherical cutoff is used by default.

Options:

• dft_u_poisson_direct:
  Direct Poisson solver. Slow but working in all cases.
  
• dft_u_poisson_isf:
  (Experimental) ISF Poisson solver on a submesh. This does not work for non-orthogonal cells nor domain parallelization.
  
• dft_u_poisson_psolver:
  (Experimental) PSolver Poisson solver on a submesh. This does not work for non-orthogonal cells nor domain parallelization. Requires the PSolver external library.
  
• dft_u_poisson_fft:
  (Default) FFT Poisson solver on a submesh. This uses the 0D periodic version of the FFT kernels.
  

Name SkipSOrbitals
Section Hamiltonian::DFT+U
Type logical
Default no

If set to yes, Octopus will determine the effective U for all atomic orbitals from the peusopotential but s orbitals. Only available with ACBN0 functional.

Name UseAllAtomicOrbitals
Section Hamiltonian::DFT+U
Type logical
Default no

If set to yes, Octopus will determine the effective U for all atomic orbitals from the peusopotential. Only available with ACBN0 functional. It is strongly recommended to set AOLoewdin=yes when using the option.