The k-points (1/3,1/3,0) and (-1/3,2/3,0), in cartesian axis and in units of 2\pi/a0, are not equivalent.
Paolo On Sun, May 29, 2016 at 6:55 AM, lyzhao <[email protected]> wrote: > Dear all, > I ran a band structure calculation at some high symmetry k-points for a > hexagonal structure (SiC 111). > I try the following two sets of k-points: > S1. > K_POINTS > 3 > 0.000 0.000 0.000 1.0 > 0.333 0.333 0.000 1.0 > 0.500 0.000 0.000 1.0 > S2. > K_POINTS > 3 > 0.0 0.0 0.0 1 > -0.333 0.667 0.000 1 > 0.000 0.500 0.000 1 > > S1 leads to the following energy band: > k = 0.0000 0.0000 0.0000 ( 1139 PWs) bands (ev): > -17.6202 -7.0494 -4.2017 -4.2017 -0.4467 1.5150 1.6453 2.3677 > k = 0.3330 0.3330 0.0000 ( 1095 PWs) bands (ev): > -15.2584 -10.1839 -6.6316 -4.3186 0.2328 1.6659 3.8224 4.8909 > k = 0.5000 0.0000 0.0000 ( 1096 PWs) bands (ev): > -15.1008 -10.7511 -5.7976 -4.1069 -0.3499 0.3805 4.1445 5.3833 > highest occupied, lowest unoccupied level (ev): -4.1069 -0.4467 > however, S2 leads to: > k = 0.0000 0.0000 0.0000 ( 1139 PWs) bands (ev): > -17.7480 -7.1365 -4.3482 -4.3482 -0.5055 1.5128 1.6485 2.3416 > k =-0.3330 0.6670 0.0000 ( 1092 PWs) bands (ev): > -15.8503 -9.8006 -5.8672 -4.9789 0.6816 0.8106 3.0639 4.2245 > k = 0.0000 0.5000 0.0000 ( 1102 PWs) bands (ev): > -15.1554 -10.1200 -7.9378 -4.0954 0.0949 3.2276 4.3675 4.3703 > highest occupied, lowest unoccupied level (ev): -4.0954 -0.5055 > > The differences between two results seem to be large. > The differences between two jobs are only the setting of k-points. > The input file is as follow: > ********************************************* > &control > calculation='scf' > restart_mode='from_scratch', > prefix='SiC111' > / > &system > ibrav=0,nat=2,ntyp=2 > ecutwfc = 15.0, occupations='fixed' > nbnd=8 > / > &electrons > diagonalization='david', > conv_thr = 1.0d-10, > mixing_beta = 0.5, > startingwfc='random', > / > ATOMIC_SPECIES > Si 28.06 Si.pbe-mt_gipaw.UPF > C 12.01 C.pbe-mt_gipaw.UPF > K_POINTS > 3 > 0.000 0.000 0.000 1.0 > 0.333 0.333 0.000 1.0 > 0.500 0.000 0.000 1.0 > > CELL_PARAMETERS (angstrom) > 2.6844596 -1.5498735 0.0000000 > 0.0000000 3.0997470 0.0000000 > 0.0000000 0.0000000 20.0077731 > ATOMIC_POSITIONS (crystal) > C 0.000000 0.000000 0.500000 > Si 0.333333 -0.333333 0.500000 > ********************************************* > > > Any help will be appreciated. > > Youzhao Lan > Zhejiang Normal University, > China. > -------------------------------------------------------- > > > > > > > ________________________________ > 2016-05-29 12:42:52 > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum -- Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222 _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
