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Hi all,
I am trying to calculate the bandgap in some amorphous system and was wondering if anyone has any idea on what is the best approach to create the KPOINTS file, as I am not sure how to do so because we do not have long range order in amorphous material hence specifying high symmetry points would be challenging. I have attached an example input files for my calculation; the way I created this structure is through melt-quench AIMD, ie. first I heated up system (melting phase) using NVT ensemble, then cooled that down (equilibration phase), and finally I quenched the structure (quench phase) up to room temperature. Then I used this structure as starting pouint to calculate the band structure : 1-first I relaxed the structure 2-then I did a scf calculation and got the CHGCAR file, 3-and for dos calculation and band calculations I used the charge density file from scf and used CONTCAR from relaxed structure from first step ; the DOS calculations go through, however for generating KPATH and high symmetry points in band structure calculation I am not sure how to create that in vaspkit, as I am not sure if any of 1D,2D, and 3D structures in vaspkit options be the case. Also I should note that I created the amorphous system in gamma point only.
any help is greatly appreciated.
Thank you,
Best,
Sahar

Dear sahar_bayat,

In principle the k-point path you choose for the bands calculation should be consistent with the type of lattice you define in your POSCAR. However, if the system is very large I am not sure you will see dispersive bands, so the band gap at Gamma will probably be enough. I suggest that you try to reproduce the bands with a few k-points along the path just to see if there is enough dispersion that justifies a calculation with more points.

Kind regards,
Pedro