Analysis

Plotting interpolated band structure

To plot the interpolated band structure, set 'Wannier.Interpolated.Bands' to be 'on'.

     Wannier.Interpolated.Bands             on    # on|off, default=off

Other necessary settings, like k-path and sampling density along each path, are borrowed from those for plotting band dispersion in OpenMX. Therefore, the keyword 'Band.dispersion' should be set as 'on' in order to draw interpolated band structure. After convergence, interpolated band dispersion data will be found in a file with the extension name '.Wannier_Band', which has the same format as '.Band' file. As an example, the interpolated band structure of Si in diamond structure is shown together with its original band structure in Fig. 34(a).

Figure: (a) The interpolated band structure (symbolic line) of Si in diamond structure is compared with original band structure (solid line). (b) One of the eight converged MLWFs from four valence states and four conduction states near Fermi level of Si in diamond structure. It is obtained with an initial guess of sp3 hybrid.

Plotting MLWF

To plot the converged MLWFs, change the keyword 'Wannier.Function.Plot' to be 'on'. The default value of it is 'off'.

   Wannier.Function.Plot                  on         # default off
   Wannier.Function.Plot.SuperCells      1 1 1       # default=0 0 0

If it is turned on, all the MLWFs will be plotted. They are written in Gaussian Cube file format with the extension file name like '.mlwf1_4_r.cube'. The file is named in the same style as HOMO or LUMO molecular orbitals files. The first number after '.mlwf' indicates the spin index and the following one are index of MLWFs and the last letter 'r' or 'i' means the real or imaginary part of the MLWF. Users can set the supercell size for plotting MLWF. It is defined by the keyword 'Wannier.Function.Plot.SuperCells'. '1 1 1' in the above example means that the unit cell is extended by one in both the plus and minus directions along the a-, b-, and c-axes by putting the home unit cell at the center, and therefore the MLWFs are plotted in an extended cell consisting of $27~(=(1*2+1)*(1*2+1)*(1*2+1))$ cells in this case. Figure 34(b) shows one of the eight converged MLWFs from four valence states and four conduction states near Fermi level of Si in diamond structure.