WANPROJ

The WANPROJ file is generated after Wannierization by setting LWRITE_WANPROJ = True. It contains the Wannier transformation matrices, $U_{mn \mathbf{k}}$, that transform the Kohn-Sham Bloch orbitals into the localized Wannier orbitals.

If WANPROJ is present, VASP skips the Wannierization procedure and reads the transformation matrices from this file instead.

Format

The file format is logically split into a header section and a section that contains the actual transformation matrix, $U_{mn \mathbf{k}}$. On each line of the file, different values are separated by one or more whitespace characters. There are no empty lines in the WANPROJ file.

Header

The header section contains the array dimensions of $U_{mn \mathbf{k}}$ as well as a list of k-points. It is structured as follows:

• The first line contains a comment
• The second line contains a list of integers
  • ISPIN: number of spin channels (either 1 or 2)
  • NKPTS: number of k-points in the full first Brillouin zone
  • NB_TOT: number of Kohn-Sham bands
  • NW: number of Wannier orbitals
• The next NKPTS lines contain information about the k-points
  • The first value is an integer and gives the index of the corresponding k-point
  • The second, third and fourth values are the x, y and z coordinates of the k-point expressed in direct coordinates of the reciprocal lattice

Transformation matrix

The transformation matrix is written as blocks of data. Each block corresponds to a particular spin channel and a particular k-point.

• The first line in each block contains information about the block
  • The first value is an integer and labels the current spin channel (either 1 or 2)
  • The second value is also an integer and counts the total number of bands that participate in the Wannier transformation at the current k-point (some bands may not participate due to being outside an energy window or being explicitly excluded from the transformation)
  • The third, fourth and fifth values are the x, y and z coordinates of the current k-point expressed in direct coordinates of the reciprocal lattice
• Each subsequent line in the block contains one matrix element of $U_{mn \mathbf{k}}$
  • The first value is the index $n$ of the Kohn-Sham band
  • The second values is the index $m$ of the Wannier orbital
  • The third and fourth values are the real and imaginary part of the corresponding matrix element