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Hybrids

This page gives hints on how to use hybrid functionals with the ABINIT package.

Introduction

The Fock exchange term has been implemented in ABINIT, both in the norm- conserving pseudopotential framework and in the PAW one. Some details about the implementation in ABINIT can be found here.
For an ABINIT user, to make a calculation of Fock exchange:
- do a first GGA dataset for the ground state
- do a second dataset for the Fock calculation choosing ixc=40-42 (HF, PBE0, PBE0-⅓), -402 (B3LYP-Libxc), -406 (PBE0-Libxc), -456 (PBE0-⅓ Libxc), or -427, -428 (HSE03, HSE06).

The energy, forces and stresses are available in the norm-conserving and PAW frameworks.
A one-shot G0W0 calculation can follow, only in the norm-conserving case at present.

Parallelism is available for spin and k-points np_spkpt, as well as over occupied bands nphf.

Warning

Use istwfk=1, iscf=2, paral_kgb=0, paral_atom=0.
The efficiency of the calculation is not optimal. Work is in progress concerning this point.

compulsory:

  • ixc Index of eXchange-Correlation functional

basic:

useful:

  • auxc_ixc AUxiliary XC functional for hybrid functional, IXC number
  • auxc_scal AUxiliary XC functional for hybrid functional- SCALing factor
  • fock_icutcoul Integer that governs the CUT-off for COULomb interaction
  • fockdownsampling FOCK operator, k-grid DOWNSAMPLING
  • nbandhf Number of BANDs for (Hartree)-Fock exact exchange
  • nphf Number of Processors for (Hartree)-Fock exact exchange
  • wfmix WaveFunctions MIXing factor

expert:

  • hyb_mixing HYBrid MIXING coefficient for unscreened fock operator
  • hyb_mixing_sr HYBrid MIXING coefficient for Short-Range screened fock operator
  • hyb_range_dft HYBrid RANGE for the DFT leftover from the screened fock operator
  • hyb_range_fock HYBrid RANGE for the screened FOCK operator
  • ixc_sigma Index of eXchange-Correlation functional used for self-energy calculations (SIGMA)
  • nkpthf Number of K - Points for (Hartree) Fock exact exchange
  • nnsclohf Number of Non-Self Consistent LOops for (Hartree)-Fock exact exchange

internal:

Selected Input Files

libxc:

paral:

v7: