KdotP
Name KdotPCalcSecondOrder
Section Linear Response::KdotP
Type logical
Default false
If true, calculates second-order response of wavefunctions as well as first-order response.
Note that the second derivative of the Hamiltonian is NOT included in this calculation.
This is needed for a subsequent run in CalculationMode = em_resp with EMHyperpol.
Name KdotPCalculateEffectiveMasses
Section Linear Response::KdotP
Type logical
Default true
If true, uses kdotp perturbations of ground-state wavefunctions
to calculate effective masses. It is not correct for degenerate states.
Name KdotPEta
Section Linear Response::KdotP
Type float
Default 0.0
Imaginary frequency added to Sternheimer equation which may improve convergence.
Not recommended.
Name KdotPOccupiedSolutionMethod
Section Linear Response::KdotP
Type integer
Default sternheimer_eqn
Method of calculating the contribution of the projection of the
linear-response wavefunctions in the occupied subspace.
Options:
- sternheimer_eqn:
The Sternheimer equation is solved including the occupied subspace,
to get the full linear-response wavefunctions.
- sum_over_states:
The Sternheimer equation is solved only in the unoccupied subspace,
and a sum-over-states perturbation-theory expression is used to
evaluate the contributions in the occupied subspace.
Name KdotPUseNonLocalPseudopotential
Section Linear Response::KdotP
Type logical
Default true
For testing purposes, set to false to ignore the term $-i \left[\vec{r}, V\right]$ in
the $\vec{k} \cdot \vec{p}$ perturbation, which is due to non-local pseudopotentials.
Name KdotPVelMethod
Section Linear Response::KdotP
Type integer
Default grad_vel
Method of velocity calculation.
Options:
- grad_vel:
$-i \left(\nabla + \left[r, V_{\rm nl} \right] \right)$
- hcom_vel:
As a commutator of the position operator and Hamiltonian, $-i \left[ r, H \right]$.