[Pw_forum] w90: existing...non symmetric k points neighbours

[Nicola Marzari]

> Elie Moujaes wrote:
>   
>> Dear All, I am trying to run the wannier90.x command for graphene and I 
>> keep on having the following error:
>>  
>>
>> Exiting.......
>>  Non-symmetric k-point neighbours!
>>
>>  
>> I have changed the grid points but in vain. Please anyone can tell me 
>> how can i avoid this error. Here is the list of k-points I am using:
>>  
>>  


Jonathan Yates has kindly answered to this in the wannier forum - 
please  post
here only after not having received any replies there. And example 10 in the
distribution is graphite. Basically you need a homogenous grid in 2d, so 
that
the keypoints are equispaced in a tringaular lattice. In the 
perpendicular direction,
you do not need k-point sampling, since there is no band dispersion in 
that direction
for an isolated system.


                   nicola


-- 
---------------------------------------------------------------------
Prof Nicola Marzari   Department of Materials Science and Engineering
13-5066   MIT   77 Massachusetts Avenue   Cambridge MA 02139-4307 USA
tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu