[Pw_forum] Yet another question about graphene bandstructure

[Hadi Arefi]

Dear Julia,

They are of course in the reciprocal space no matter you want them to be or not! If your K-mesh is dense enough (which is not in your current input) and along the right paths (Which still aren't: GAMMA-to-M-to-K-to-GAMMA), then there are some parameters you need to check such as smearing/K-points/ecut/ecutrho convergence.

Your smearing looks high to me and your ecut is too much for a PAW pseudo potential that you are using. Also you need to specify ecutrho as well because the default value is used in the case of norm conserving one.

HTH.

Hadi.

-----Original Message-----
From: pw_forum-bounces at pwscf.org [mailto:pw_forum-bounces at pwscf.org] On Behalf Of jbobak
Sent: 10 March 2014 18:14
To: PWSCF Forum
Subject: Re: [Pw_forum] Yet another question about graphene bandstructure

Hi Hadi,

Thank you for your quick response! I have tried that K-path also (I remain confused as to whether K-paths are in real or reciprocal space, so I tried
both) with a similar result.

Julia

> Dear Julia,
>
> I guess your K-path is not entirely coincides with the high symmetry 
> points for graphene. Make sure you span the following routes with 
> enough
> K:
>
> 0	0	0
> 0.666	0.333	0
> 0.5	0.5	0
> 0	0	0
>
>
> HTH,
>
> Hadi.
> -----Original Message-----
> From: pw_forum-bounces at pwscf.org [mailto:pw_forum-bounces at pwscf.org] 
> On Behalf Of jbobak
> Sent: 10 March 2014 17:04
> To: pw_forum at pwscf.org
> Subject: [Pw_forum] Yet another question about graphene bandstructure
>
> Hi all,
> I've searched the forum for this question, but nobody seems to be 
> having quite the same issue, so I expect I'm doing something uniquely 
> stupid. I am trying to calculate the band structure of graphene (using 
> Espresso
> 5.0.3) for practice before I use a more complicated system. I do an 
> SCF calculation with just the unit cell (2 atoms) with automatic 
> k-points 18
> 18 1 0 0 0. Then I do a band structure calculation with k-points as
> follows:
>
> K_POINTS {tbipa}
> 7
> 0.00000 0.00000 0.00000 1
> 0.28868 0.16666 0.00000 1
> 0.57735 0.33333 0.00000 1
> 0.43301 0.41666 0.00000 1
> 0.28868 0.50000 0.00000 1
> 0.14435 0.25000 0.00000 1
> 0.00000 0.00000 0.00000 1
>
> I then run bands.x, followed by plotband.x which I run interactively.
> Everything works fine in that I get no errors, but the bandstructure 
> plot is wrong (see attached pdf). The bands should cross at the K 
> point. I think the problem has something to do with the k-points, 
> which is why I have reproduced them above, but I have also attached 
> the relevant input and output files. Could it be because the 
> high-symmetry k-points I selected are not present in the automatically selected grid?
>
> Thank you so much for any help,
> Julia Bobak
>
> Research Assistant
> University of Victoria, Victoria, BC, CANADA
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum
>


_______________________________________________
Pw_forum mailing list
Pw_forum at pwscf.org
http://pwscf.org/mailman/listinfo/pw_forum