First you need to perform scf calculation by using G-centered k-point and then nscf calculation. Then you can create xcrysden input file by using https://github.com/MTD-group/Fermi-Surface script and plot it by Xcrysden program.

Best Wishes!

Do you install xcrysden? In xrysden, there is an option to open this file directly. See the xrysden user guide.

Then go to file menu and here you will see an option to open bxsf file format. Open it and you need to select the number of energy band (that cross the fermi level). It will then show you Fermi surface.

It should give error, since it does not support this mode. You must provide uniform k-point (non-shifted).

What do you mean by different from example? generated k-point? or fermi surface?

It should be change according to symmetry of the crystal. Does it for same system?

You must use same k-point that used in scf/nscf calculation.

Is it for same symmetry? If not, then it is okay.

I think that it should be, however, it seems to be buggy code. It is better to use quantum espresso which contains all necessary codes.

Like vasp, you need to run scf calculation and then nscf calculation. Then run fs.x to generate Fermi surface data in xcrysden format. In pp example folder, there is an example how you can draw Fermi surface. Please the the qe example directory.

No, It is totally different.

You are most welcome!

I donot find the qe example directory download link. You can send email to [email protected] and I will send you a personal link to download it. Please

note that I am unavailable for three days, so I can send you after 25 Feb 2019.

I am afriad you are using python 2 program but the python script is for python 3. If you want to use python 2, you need to add this sentence "from __future__ import division" to your python script, as "division" is different for python 2 and python 3. Now your python script looks like this:

## -- codes begin -- ##

from __future__ import division # for Python 2;

import os.path

from numpy import *

data=loadtxt("input.dat", unpack='true')

nx=int(data[0,0])

ny=int(data[1,0])

nz=int(data[2,0])

nkpt=(nx+1)*(ny+1)*(nz+1)

fp2 = open("KPOINTS","w")

fp2.write("Explicit k-points list for Fermi surface")

fp2.write('\n')

fp2.write("{}".format(nkpt))

fp2.write('\n')

fp2.write("Reciprocal lattice")

fp2.write('\n')

for i in range(nx+1):

for j in range(ny+1):

for k in range(nz+1):

fp2.write(" {:.15f} {:.15f} {:.15f} {}".format(i/nx,j/ny,k/nz,1))

fp2.write('\n')

fp2.close()

## -- codes end --#

Codes taken from here:

http://blog.sciencenet.cn/home.php?mod=space&uid=1502061&do=blog&id=1093325

By the way, I find a quite good tutorial here: https://github.com/MTD-group/Fermi-Surface

When you open fermi surface input file (generated by vasp and script), you will find menu bar to put the Fermi energy and select the different band.