The ABINIT Users Mailing List ( CLOSED )

[Matteo Giantomassi <gmatteo@pcpm.ucl.ac.be>]

Quoting hyello25@gmail.com:

> HelloC
>    I konw the work of Fermi surface using abinit is under developing.
> But i want to try to do a FS job. How can i practise it?
>    I am just clear about this work should be put in a e-ph calculation
> with special input kptopt==1 and nshiftk==1 in GS calculation, and
> prtfsurf==1. However, in the output files i can not find the FS files in
> the format bxsf for Xcrysden.
>    
>   Need help, thanks.
>      
> 

I think the problem you are encountering is due to 
the use of a k-grid which is not compatible with Xcrysden.

First of all, are you sure that shiftk is equal to 0.0 0.0 0.0 ? 
Remember, indeed, that the default value for shiftk is 0.5 0.5 0.5 while 
it must be 0.0 0.0 0.0 in order to plot the FS
 
Moreover, if your k-mesh is defined using kptrlatt instead of ngkpt, 
please check that all the off-diagonal elements of the matrix are zero: 

kptrlatt 5 0 0        # this works 
         0 5 0 
         0 0 5 

kptrlatt 5 2 0        # wrong
         0 5 1
         0 0 5


If the k-mesh is not generated following these constraints, the 
code will complain writing an error message on the log file, 
and no FS output will be created.  

By the way: 
Since version 5.3.5, it's not necessary to run an e-ph calculation 
if one is only interested in the FS output. 
You can obtain the BXSF file by just running a GS calculation with 
prtfsurf=1 and a suitable k grid.

Best Regards, 
Matteo Giantomassi

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