[QE-users] band.x could not find the symmetry from the k path generated by Xcrysden 1.6.2

[liuyang]

Hello everyone,


I'm a new user of QE-6.5. and I'm following the first tutorials on QE official website (https://gitlab.com/QEF/material-for-ljubljana-qe-summer-school).


In the 2nd example of Day 1 training, the band structure of graphene should be calculated from the given input files: pw.graphene.scf.in, and pw.graphene.bands.in. After obtaining the output files of scf and bands, band.x should be called to extract the information of bands. The k path in file pw.graphene.bands.in goes: 
K_POINTS {crystal_b}
4
# Gamma-K-M-Gamma
   0.0000000000     0.0000000000     0.0000000000     20
   0.3333333333     0.3333333333     0.0000000000     10
   0.0000000000     0.5000000000     0.0000000000     17
   0.0000000000     0.0000000000     0.0000000000     0


The calculation of the example files ends normally. However, if I use the k path generated by Xcrysden, calling band.x ends with errors. 


Xcrysden gives k path like:
K_POINTS crystal
          20
        0.0000000000    0.0000000000    0.5000000000    1.0
        0.0416662500    0.0416662500    0.5000000000    1.0
        ......
The error information in the output file of band.x calculation is " Error in routine smallgk (1): Not a group". I then go to the source file of routine smallgk, and find that the error may be due to inability of finding symmetries from the given k points.


So how can I make symmetries be recognized in this situation?


Thank you very much!


Regards


Yang LIU
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20200611/c23b4390/attachment.html>