[Wien] case.klist_band for band structure calculation having R-3c spacegroup

Gavin Abo gsabo at crimson.ua.edu
Mon May 16 13:54:17 CEST 2016


The xcrysden.klist outputted by XCrysDen [ 
http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg12861.html 
] and used as the case.klist_band input for WIEN2k for an R lattice 
should use the primitive reciprocal vectors [ 
http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg12479.html 
].

As it says on the XCrysDen website, XCrysDen uses the primitive setting 
as input, but the conventional setting can be viewed for informational 
purposes [ http://www.xcrysden.org/doc/kpath.html ].

On 5/16/2016 12:50 AM, saurabh singh wrote:
> Thank you so much Peter BLAHA Sir for your valuable suggestion .
> I have another query, In the Bilbao crystallographic server the 
> k-vector description is given in the two basis i.e. *Primitive basis 
> and **Conventional basis *. In the user manual of Wien2k section 7.5.3 
> page 120, ix,iy,iz, defines the k-vector, where x= ix/idv etc. We use 
> cartesian coordinates in units of 2π/a, 2π/b, 2π/c for P,C,F and B 
> cubic, tetragonalnand orthorhombic lattices, but internal coordinates 
> for H and monoclinic/triclinic lattices.
> For rhombohedral there is no suggestion given.
> Since we need to select the k-point manually in the xcrysden for high 
> symmetric k-point, therefore it is very important to choose the 
> correct basis coordinate. therefore I would like to know that in 
> general for Rhombohedral space group, which basis coordinate 
> (Primitive or Conventional) given in the Bilbao server should be used 
> for making the case.klist_band.
>  I have two choice in xcrysden:
> 1. Primitive Brillouin zone: if I choose this option in xcrysden to 
> select the k-point coordinate then should i use the primitive basis 
> coordinate of high k-point from the Bilbao server.
> 2. Conventional Brillouin zone: for this should i use the conventional 
> basis coordinate from the Bilbao server.
>
> Please give your suggestion for choosing the proper basis coordinate 
> of k-point for rhmbohedral lattice from Bilbao server.
>
> On Sun, May 15, 2016 at 10:48 PM, saurabh singh 
> <saurabhiitmandi at gmail.com <mailto:saurabhiitmandi at gmail.com>> wrote:
>
>     Dear All Wien2k users,
>
>     We want to calculate the band structure of LaCoO3 compound. The
>     space group of this compound is R-3c (No. 167). In the Wien2k user
>     manual, it is suggested for R lattice to use rhombohedral
>     coordinates. Therefore we made the case.structure file using
>     lattice parameters a=b= 10.2541 Bohr, c= 24.5494, alpha=beta=90
>     degree, gamma = 120 degree, and converted rhombohedral coordinates
>     for each atom. When we try to make case.klist_band file by
>     selecting the case.structure folder path in xcrysden, it says "
>     the guessed bravais lattice type: not supported (the XSF's group
>     number is 7). We tried the two different way to get the
>     case.klist_band as follows:
>
>     1) Firstly, we have changed the lattice parameters in
>     case.structure file in accordance to rhombohedral structure. We
>     thought if the lattice parameters and atomic coordinate both will
>     be accordance to rhombohedral then xcrysden can recognize the
>     case.struct file. But again case.struct file does not recognized
>     by xcrysden.
>
>     2) Secondly, we took the hcp.klist file given in wien2k SRC
>     folder, which is as follows:
>     GAMMA  0    0    0   40  2.0-0.5 1.5       Template for hcp structure
>                   1    0    0   40  2.0
>                   2    0    0   40  2.0
>                   3    0    0   40  2.0
>                   4    0    0   40  2.0
>                   5    0    0   40  2.0
>                   6    0    0   40  2.0
>                   7    0    0   40  2.0
>                   8    0    0   40  2.0
>                   9    0    0   40  2.0
>     SIGMA  10    0    0   40  2.0
>                  11    0    0   40  2.0
>                  12    0    0   40  2.0
>                  13    0    0   40  2.0
>                  14    0    0   40  2.0
>                  15    0    0   40  2.0
>                  16    0    0   40  2.0
>                  17    0    0   40  2.0
>                  18    0    0   40  2.0
>                  19    0    0   40  2.0
>     M            20    0    0   40  2.0
>                  29    2    0   60  2.0
>                  28    4    0   60  2.0
>                  27    6    0   60  2.0
>                  26    8    0   60  2.0
>                  25   10    0   60  2.0
>                  24   12    0   60  2.0
>                  23   14    0   60  2.0
>                  22   16    0   60  2.0
>                  21   18    0   60  2.0
>     K           20   20    0   60  2.0
>                  19   19    0   60  2.0
>                  18   18    0   60  2.0
>                  17   17    0   60  2.0
>                  16   16    0   60  2.0
>                  15   15    0   60  2.0
>                  14   14    0   60  2.0
>                  13   13    0   60  2.0
>                  12   12    0   60  2.0
>                  11   11    0   60  2.0
>     LAMBDA10   10    0   60  2.0
>                   9    9    0   60  2.0
>                   8    8    0   60  2.0
>                   7    7    0   60  2.0
>                   6    6    0   60  2.0
>                   5    5    0   60  2.0
>                   4    4    0   60  2.0
>                   3    3    0   60  2.0
>                   2    2    0   60  2.0
>                   1    1    0   60  2.0
>     GAMMA  0    0    0   60  2.0
>                   0    0    1   20  2.0
>                   0    0    2   20  2.0
>                   0    0    3   20  2.0
>                   0    0    4   20  2.0
>     DELTA    0    0    5   20  2.0
>                   0    0    6   20  2.0
>                   0    0    7   20  2.0
>                   0    0    8   20  2.0
>                   0    0    9   20  2.0
>     A            0    0   10   20  2.0
>     END
>
>     We renamed this hcp.klist file as case.klist_band and used it for
>     band structure calculation. The calculated band structure gives
>     the indirect band gap which is almost equal to the band gap
>     obtained from SCF calculation.
>
>     My question is, whether we can use the hcp.klist (given in Wien2k
>     SRC folder) as case.klist_band for band structure calculation if
>     the compound have R-3c space group and having the hexagonal
>     lattice parameter and rhombohedral atomic coordinate in the
>     case.struct file. Please let me know I am doing right or there is
>     some different way to do it.
>
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