4.6 Wannier functions

There are several Wannier-related utilities in PostProc:

1. The "Poor Man Wannier" code pmw.x, to be used in conjunction with DFT+U calculations: see Example 05.
2. The interface with Wannier90 code, pw2wannier.x: see the documentation in W90/ (you may install the Wannier90 plug-in via make w90 ). For spin-current matrix elements, implemented in routine compute_shc: ``it writes .sIu and .sHu files used for WANNIER-BERRI (https://github.com/stepan-tsirkin/wannier-berri/), and also will be utilized through postw90.x (https://github.com/manxkim/wannier90/tree/SHC/src) in Wannier90. In WANNIER-BERRI, .sHu and .sIu files can be used to calculate the quantity "opt_SHCryoo". In Wannier90, add "berry_task = shc" and "shc_ryoo=.true.". in the input parameters of postw90.x. They activate the calculation of SHC using .sHu and .sIu.''
3. The wannier_ham.x code generates a model Hamiltonian in Wannier functions basis: see PP/examples/WannierHam_example/.

Note that the wfdd.x code has been moved to CP.