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:[email protected]] 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
