[Wien] Band gap calculation of C diamond structure

[pieper]

The problem will be in the .struct you started from. You say yourself 
that the structure does not look like diamond in xcrysden. Don't change 
the .struct file in a case directory and restart the scf. The 
calculation relies on consistency of various input files.

The standard advice seems to be:

start a new case in fresh directory,
generate (preferably from w2web) a new struct file,
inspect it with xcrysden (there is no meaning in wasting CPU-time for 
scf-cycles on wrong structures),
proceed with the initialization (check the nearest neighbor distances in 
outputnn to see if you got the units in struct right)
and start the scf only when everything went ok.

... and keep fingers crossed


---
Dr. Martin Pieper
Karl-Franzens University
Institute of Physics
Universitätsplatz 5
A-8010 Graz
Austria
Tel.: +43-(0)316-380-8564


Am 13.02.2017 09:18, schrieb Abhilash Patra:
> Dear Wien2k users,
> I am running WIEN2k_14.2 on my  Lenovo workstation with fedora 23. I
> want to calculate the band gap of C, Si, and Ge with the diamond
> structure.
> To generate my struct file I used: No. of Atoms-1, Space group-
> 227_Fd-3m and a=b=c=3.567 and one carbon atom at (0,0,0). Then set RMT
> automatically (reduce RMT--0%). Then it set RMT to 1.18. I initiate
> calculation with all the default values and run SFC as there is no
> warning in the STDOUT.
> But when I see the structure in the Xcrysden the figure is not looking
> like diamond structure. And the band plot shows no gap
> 
> : GAP: -99999.   Ry = -9999.    eV  ( metallic )
> 
> I have already tried the structure : Atom=1, FCC, a=3.567, one atom at
> (0,0,0) and other position at (0.25,0.25,0.25). This gives
> diamond-likee structure but in the STDOUT file it gives some warning
> like
> 
> warning: !!! Struct file is not consistent with space group found.
> Number and name of space group: 227 (F d -3 m) [origin choice 2]
> 
> and SCF gives error like
> 
> head: cannot open ‘WIEN2k.inm’ for reading: No such file
> or directory
> head: cannot open ‘WIEN2k.inm’ for reading: No such file
> or directory
> no WIEN2k.clmsum(_old) file found, which is necessary for lapw0 !
> 
>>   stop error
> 
> Please suggest me about the struct file which will give the results
> for all like LDA, PBE and mGGAfunctionals
> 
> Thanks
> 
> --
> 
> Abhilash Patra
> Research Scholar(Ph.D.)
> School of Physical science
> NISER,BBSR
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