As a small addendum, you may also need to ensure that the fft size in lapw0 (via case.in0) is a multiple of 6 along a & b to preserve equivalence of atoms.
--- Professor Laurence Marks Department of Materials Science and Engineering Northwestern University http://www.numis.northwestern.edu Corrosion in 4D http://MURI4D.numis.northwestern.edu Co-Editor, Acta Cryst A "Research is to see what everybody else has seen, and to think what nobody else has thought" Albert Szent-Gyorgi On Dec 23, 2015 06:57, "Peter Blaha" <pbl...@theochem.tuwien.ac.at> wrote: > a) As expected, something is wrong with your structure. > > It should be a hexagonal lattice (H and not P) and the angle gamma > should be 120 and not 60, and also the positions need to be changed then. > > With an "H" lattice, wien2k keeps the symmetry properly and is less > affected by rounding errors. > > b) And secondly, you did not answer, how you got the "gap" (from > scf-file, output1 or bandstructure or DOS ???) > > Forget DOS (there is a smearing parameter set by default !) > > when you use a H lattice and meshes which can be divided by 3 (because K > has 1/3,1/3,0 coordinates and only with a mesh like 3 3 1, 6 6 1, 9 9 > 1, ... the "K"-point is in the mesh), you can use :GAP from scf, > otherwise NOT. (best is to use a mesh conpatible with 2 and 3, so 6,6,1 > or 12,12,1 ..., because this includes also the M point. > > > > On 12/23/2015 01:22 PM, Islam, Md F wrote: > > Hi Prof Blaha, > > > > Here is the structure I am using. I tried to be as precise as > possible with position coordinates. > > I think size of the vacuum is sufficiently large so that > supercell-supercell interaction is negligible. > > So far what I have got is that with LDA xc if I use 25 x 25 x 1 k-mesh > there is a gap at the Fermi > > level (which passes through K point) but if I use 30 x 30 x 1 k-mesh, > gap closes but DOS is not > > zero at the Fermi level (about 0.001/eV). Please let me know if I am > doing anything wrong with > > this calculation. > > > > > > Thanks, > > Fhokrul > > > > > > Graphene > > P LATTICE,NONEQUIV.ATOMS: 2 > > MODE OF CALC=RELA unit=bohr > > 4.647800 4.647800 30.000000 90.000000 90.000000 60.000000 > > ATOM -1: X=0.00000000 Y=0.00000000 Z=0.50000000 > > MULT= 1 ISPLIT= 8 > > C NPT= 781 R0=0.00010000 RMT= 1.3200 Z: 6.0 > > LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000 > > 0.0000000 1.0000000 0.0000000 > > 0.0000000 0.0000000 1.0000000 > > ATOM -2: X=0.66666667 Y=0.66666667 Z=0.50000000 > > MULT= 1 ISPLIT= 8 > > C NPT= 781 R0=0.00010000 RMT= 1.3200 Z: 6.0 > > LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000 > > 0.0000000 1.0000000 0.0000000 > > 0.0000000 0.0000000 1.0000000 > > 12 NUMBER OF SYMMETRY OPERATIONS > > -1-1 0 0.00000000 > > 0 1 0 0.00000000 > > 0 0-1 0.00000000 > > 1 > > -1-1 0 0.00000000 > > 0 1 0 0.00000000 > > 0 0 1 0.00000000 > > 2 > > -1-1 0 0.00000000 > > 1 0 0 0.00000000 > > 0 0-1 0.00000000 > > 3 > > -1-1 0 0.00000000 > > 1 0 0 0.00000000 > > 0 0 1 0.00000000 > > 4 > > 0 1 0 0.00000000 > > -1-1 0 0.00000000 > > 0 0-1 0.00000000 > > 5 > > 0 1 0 0.00000000 > > -1-1 0 0.00000000 > > 0 0 1 0.00000000 > > 6 > > 0 1 0 0.00000000 > > 1 0 0 0.00000000 > > 0 0-1 0.00000000 > > 7 > > 0 1 0 0.00000000 > > 1 0 0 0.00000000 > > 0 0 1 0.00000000 > > 8 > > 1 0 0 0.00000000 > > -1-1 0 0.00000000 > > 0 0-1 0.00000000 > > 9 > > 1 0 0 0.00000000 > > -1-1 0 0.00000000 > > 0 0 1 0.00000000 > > 10 > > 1 0 0 0.00000000 > > 0 1 0 0.00000000 > > 0 0-1 0.00000000 > > 11 > > 1 0 0 0.00000000 > > 0 1 0 0.00000000 > > 0 0 1 0.00000000 > > 12 > > > > > > > > > > ________________________________________ > > From: wien-boun...@zeus.theochem.tuwien.ac.at [ > wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of Peter Blaha [ > pbl...@theochem.tuwien.ac.at] > > Sent: Tuesday, December 22, 2015 3:29 PM > > To: A Mailing list for WIEN2k users > > Subject: Re: [Wien] Graphene bandstructure > > > > The two eigenvalues at K must be identical by symmetry. > > > > If you have a splitting of some meV it means that your structure is > > slightly wrong. > > > > Typical errors: positions of 1/3 and 2/3 must be given in full precision. > > 0.3333 is NOT 1/3 > > > > Am 22.12.2015 um 20:31 schrieb Islam, Md F: > >> Hi Prof Blaha, > >> > >> I have got the gap from plotting bandstructure as well as DOS > calculations. > >> I can see the linear dispersion at the K point just like the way it is > suppose to be > >> when I plot all the bands in eV range. But if I zoom in at the K point > in meV range, > >> I can see the gap. > >> > >> I don't think there is anything wrong with the structure. I did > check all bond lengths, > >> angles before I ran the calculations and they are correct. I suspect I > may have to adjust > >> parameters. I started to see some difference with LDA xc functional > with larger k mesh. > >> > >> > >> Thanks, > >> Fhokrul > >> > >> > >> > >> > >> ________________________________________ > >> From: wien-boun...@zeus.theochem.tuwien.ac.at [ > wien-boun...@zeus.theochem.tuwien.ac.at] On Behalf Of Peter Blaha [ > pbl...@theochem.tuwien.ac.at] > >> Sent: Tuesday, December 22, 2015 11:35 AM > >> To: A Mailing list for WIEN2k users > >> Subject: Re: [Wien] Graphene bandstructure > >> > >> Graphene is metallic by "symmetry", i.e. EF is at a 2-fold eigenvalue at > >> the K-point and bands cross with a linear dispersion. > >> > >> From where do you know that graphene has a gap in your calculations > ?? > >> > >> From :gap in the scf file or from plotting the bandstructure or ... > >> > >> It the state at K is not degenerate, you have the wrong symmetry and are > >> not doing graphene. > >> > >> Am 22.12.2015 um 16:51 schrieb Islam, Md F: > >>> Hi, > >>> > >>> I am trying to do a bandstructure calculation of graphene to > check if I can > >>> reproduce results discussed in literature (I am using a unit cell of 2 > atoms). > >>> With spin-orbit coupling, there should be a gap of the order of few > micro-eV > >>> and without spin-orbit, there should not be any gap at Dirac point. > But I am > >>> getting a gap of meV even without spin-orbit. I tried both GGA and LDA > with > >>> very dense mesh but the gap does not close. So I am wondering if anyone > >>> have any suggestion about how to do it in Wien2k. > >>> > >>> > >>> Thanks, > >>> Fhokrul > >>> _______________________________________________ > >>> Wien mailing list > >>> Wien@zeus.theochem.tuwien.ac.at > >>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > >>> SEARCH the MAILING-LIST at: > http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html > >>> > >> > >> -- > >> > -------------------------------------------------------------------------- > >> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna > >> Phone: +43-1-58801-165300 FAX: +43-1-58801-165982 > >> Email: bl...@theochem.tuwien.ac.at WIEN2k: http://www.wien2k.at > >> WWW: http://www.imc.tuwien.ac.at/staff/tc_group_e.php > >> > -------------------------------------------------------------------------- > >> _______________________________________________ > >> Wien mailing list > >> Wien@zeus.theochem.tuwien.ac.at > >> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > >> SEARCH the MAILING-LIST at: > http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html > >> _______________________________________________ > >> Wien mailing list > >> Wien@zeus.theochem.tuwien.ac.at > >> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > >> SEARCH the MAILING-LIST at: > http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html > >> > > > > -- > > > -------------------------------------------------------------------------- > > Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna > > Phone: +43-1-58801-165300 FAX: +43-1-58801-165982 > > Email: bl...@theochem.tuwien.ac.at WIEN2k: http://www.wien2k.at > > WWW: http://www.imc.tuwien.ac.at/staff/tc_group_e.php > > > -------------------------------------------------------------------------- > > _______________________________________________ > > Wien mailing list > > Wien@zeus.theochem.tuwien.ac.at > > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > > SEARCH the MAILING-LIST at: > http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html > > _______________________________________________ > > Wien mailing list > > Wien@zeus.theochem.tuwien.ac.at > > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > > SEARCH the MAILING-LIST at: > http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html > > > > -- > > P.Blaha > -------------------------------------------------------------------------- > Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna > Phone: +43-1-58801-165300 FAX: +43-1-58801-165982 > Email: bl...@theochem.tuwien.ac.at WIEN2k: http://www.wien2k.at > WWW: http://www.imc.tuwien.ac.at/staff/tc_group_e.php > -------------------------------------------------------------------------- > _______________________________________________ > Wien mailing list > Wien@zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > SEARCH the MAILING-LIST at: > http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html >
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