[CP2K-user] [CP2K:13001] Electronic Band Structure. K-sampling. Weird behaviour. BN-MoS2-BN

[hut... at chem.uzh.ch]

Hi

the &KPOINTS section defines the kp for the Kohn-Sham calculations.
WAVEFUNCTION REAL is only for very specific usage (and debugging),
please don't use it for normal use.

Once the Kohn-Sham calculation converged, you can calculate the
band structure using a finer grid with the section

    &PRINT
       &BAND_STRUCTURE
          ADDED_MOS 2
          FILE_NAME xx.bs
          &KPOINT_SET
             UNITS  B_VECTOR
             SPECIAL_POINT  Gamma 0.0 0.0 0.0
             SPECIAL_POINT  X     1.0 0.0 0.0
             NPOINTS     10
          &END
       &END BAND_STRUCTURE

This section can be automatically generated using Seek-path

https://www.materialscloud.org/work/tools/seekpath

regards

Juerg Hutter

--------------------------------------------------------------
Juerg Hutter                         Phone : ++41 44 635 4491
Institut für Chemie C                FAX   : ++41 44 635 6838
Universität Zürich                   E-mail: hut... at chem.uzh.ch
Winterthurerstrasse 190
CH-8057 Zürich, Switzerland
---------------------------------------------------------------

-----cp... at googlegroups.com wrote: -----
To: "cp2k" <cp... at googlegroups.com>
From: "Sara Fiore" 
Sent by: cp... at googlegroups.com
Date: 03/20/2020 03:17PM
Subject: [CP2K:13001] Electronic Band Structure. K-sampling. Weird behaviour. BN-MoS2-BN

                                         Dear all,  I am experiencing some problems with the band structure calculation 
   1) from the tutorial: https://www.cp2k.org/exercises:2016_uzh_cmest:band_structure_calculation 
   In &KPOINTS section there are 1-A)

 SCHEME MONKHORST-PACK 3 3 1
 why a ‚so small‘ sampling ? Maybe I am misinterpreting it and it does not work in the same way as in QuantumESPRESSO If one wants to compute band structure in QuantumESPRESSO

>From  :   https://www.materialscloud.org/explore/2dstructures/details/3bc1dfdc-6dff-4639-b680-b90ca3d6b342?nodeType=NODE)
- scf :
K_POINTS automatic

 16 16 1 0 0 0


-bands : 132 k points

 1-B) why these settings are different with respect to the default?
WAVEFUNCTIONS REAL 
FULL_GRID .TRUE.

2) my own calculation
My goal would be to compute the band-structure for MoS2 sandwiched 
between two layers of BN : BN-MoS2-BN  I am trying to compute the band structure using the k-sampling. 
attached you find my input/output files.

Bands is the file produced with CP2K

bands.set-1.csv is the file produced by the python script 
attached to the graphene example (see url above)


My problem is that I obtain weird behavior of the bands. 
Specifically, look at the K point the grey and dark green bands. 
They have a very strange behavior (sharp angle)

Can anyone help me understand what I am doing wrong?

Thankyou a lot in advance!

    
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[attachment "bands.set-1.csv" removed by Jürg Hutter/at/UZH]
[attachment "MoS2-BN.inp" removed by Jürg Hutter/at/UZH]
[attachment "bands" removed by Jürg Hutter/at/UZH]
[attachment "output" removed by Jürg Hutter/at/UZH]
[attachment "BN-MoS2-BN_zoom.png" removed by Jürg Hutter/at/UZH]
[attachment "BN-MoS2-BN.png" removed by Jürg Hutter/at/UZH]