SOC Effects

SOC

lspinorb is used for control whether or not SOC(spin-orbit coupling) effects should be considered.

Both basis_type=pw and basis_type=lcao support scf and nscf calculation with SOC effects.

Atomic forces and cell stresses can not be calculated with SOC effects yet.

Pseudopotentials and Numerical Atomic Orbitals

For Norm-Conserving pseudopotentials, there are differences between SOC version and non-SOC version.

Please check your pseudopotential files before calculating. In PP_HEADER part, keyword has_so=1 and relativistic="full" refer to SOC effects have been considered, which would lead to different PP_NONLOCAL and PP_PSWFC parts. Please be careful that relativistic="full" version can be used for SOC or non-SOC calculation, but relativistic="scalar" version only can be used for non-SOC calculation. When full-relativistic pseudopotential is used for non-SOC calculation, ABACUS will automatically transform it to scalar-relativistic version.

Numerical atomic orbitals in ABACUS are unrelated with spin, and same orbital file can be used for SOC and non-SOC calculation.

Partial-relativistic SOC Effect

Sometimes, for some real materials, both scalar-relativistic and full-relativistic can not describe the exact spin-orbit coupling. Artificial modulation can help for these cases.

soc_lambda, which has value range [0.0, 1.0] , is used for modulate SOC effect. In particular, soc_lambda 0.0 refers to scalar-relativistic case and soc_lambda 1.0 refers to full-relativistic case.