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I am new to Quantum Espresso software, and I'm trying to plot a simple band structure. While I can successfully reproduce the literature data, I feel like I need more points per line. However I cannot find this parameter in the manual of pw.x, bands.x or plotbands.x

Where is this parameter selected? Thanks!

K-point part of the 'band' calculation:

K_POINTS crystal 4 0.0000000000 0.0000000000 0.0000000000 20 0.5000000000 0.5000000000 0.0000000000 40 0.3333333333 0.6666666667 0.0000000000 60 0.0000000000 0.0000000000 0.0000000000 80
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    $\begingroup$ Could you show your pw.x input file with calculation='bands'? You can increase the number of points to be sampled between two high-symmetry points by increasing the wk(nks) value of tpiba_b or crystal_b option in the K_POINTS card. $\endgroup$ Commented Mar 19 at 13:37
  • $\begingroup$ I modified my question including what you asked :) $\endgroup$ Commented Mar 19 at 14:15
  • $\begingroup$ It seems you added the K_POINTS card from the pw.x with calculation='scf' or calculation='nscf'. This should not be used in the calculation='bands'. Use either crystal_b or tpiba_b for band structure plot and increase the number in the fourth column. $\endgroup$ Commented Mar 19 at 15:22
  • $\begingroup$ By using 'crystal_b' I obtain very strange results in the bands. On the opposite, by using 'crystal' I obtain 'the good bands', by just with very few points $\endgroup$ Commented Mar 24 at 11:33
  • $\begingroup$ What is your material and what k-path are you using? Could you add some of the details in your post such as what output you were getting previously, and what you are getting now? $\endgroup$ Commented Mar 24 at 15:14

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As suggested by Abdul Muhaymin, when making a band structure plot, use K_POINTS crystal_b or K_POINTS tpiba_b (which differ only in their units). This is buried in the pw.x documentation for K_POINTS.

tpiba_b :

Used for band-structure plots. See Doc/brillouin_zones.pdf for usage of BZ labels; otherwise, k-points are in units of 2 pi/a. nks points specify nks-1 lines in reciprocal space. Every couple of points identifies the initial and final point of a line. pw.x generates N intermediate points of the line where N is the weight of the first point.

In other words, the fourth parameter in each line k_x k_y k_z wk becomes the number of k-points between k_x k_y k_z and the k-point specified on the next line, exclusive of the endpoints.

I leave the precise calculation of how many k-points should be along each line in your hands :)

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