LSCDM
LSCDM = .TRUE. | .FALSE.
| Default: LSCDM | = .FALSE. |
Description: LSCDM switches on the selected columns of the density matrix (SCDM) method.
The selected columns of the density matrix (SCDM) method works by fitting a unitary matrix [math]\displaystyle{ U_{mn\mathbf{k}} }[/math] that transforms the basis from Bloch states [math]\displaystyle{ |\psi_{n\mathbf{k}}\rangle }[/math] obtained by VASP to a Wannier basis [math]\displaystyle{ |w_{m\mathbf{R}}\rangle }[/math].
- [math]\displaystyle{ |w_{m\mathbf{R}}\rangle = \sum_{n\mathbf{k}} e^{-i\mathbf{k}\cdot\mathbf{R}} U_{mn\mathbf{k}} |\psi_{n\mathbf{k}}\rangle. }[/math]
This is done using a one-shot method through a singular-value decomposition as proposed by A. Damle and L. Lin [1].
In order to obtain a good Wannierization, a certain level of freedom should be given to the localized orbitals to adequately accommodate the Bloch states. This is controlled by the cutoff function specified by the CUTOFF_TYPE tag and related parameters [math]\displaystyle{ \mu }[/math] (CUTOFF_MU) and [math]\displaystyle{ \sigma }[/math] (CUTOFF_SIGMA).
Related tags and articles
CUTOFF_TYPE, CUTOFF_MU, CUTOFF_SIGMA