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<DIV style="FONT-SIZE: 14pt; FONT-FAMILY: Times New Roman">Dear Paolo,</DIV>
<DIV style="FONT-SIZE: 14pt; FONT-FAMILY: Times New Roman">Thanks for your help.
</DIV>
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<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: Times New Roman">2016-05-29
16:19:55</DIV>
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<DIV><B>From:</B> <A href="mailto:p.giannozzi@gmail.com">Paolo
Giannozzi</A></DIV>
<DIV><B>Date:</B> 2016-05-29 15:39</DIV>
<DIV><B>To:</B> <A href="mailto:pw_forum@pwscf.org">PWSCF Forum</A></DIV>
<DIV><B>Subject:</B> Re: [Pw_forum] The equal k-points cannot lead to the
same energy band.</DIV></DIV></DIV>
<DIV>
<DIV>The k-points (1/3,1/3,0) and (-1/3,2/3,0), in cartesian axis and in</DIV>
<DIV>units of 2\pi/a0, are not equivalent.</DIV>
<DIV> </DIV>
<DIV>Paolo</DIV>
<DIV> </DIV>
<DIV>On Sun, May 29, 2016 at 6:55 AM, lyzhao <lyzhao@zjnu.cn> wrote:</DIV>
<DIV>> Dear all,</DIV>
<DIV>> I ran a band structure calculation at some high symmetry k-points for a</DIV>
<DIV>> hexagonal structure (SiC 111).</DIV>
<DIV>> I try the following two sets of k-points:</DIV>
<DIV>> S1.</DIV>
<DIV>> K_POINTS</DIV>
<DIV>> 3</DIV>
<DIV>> 0.000 0.000 0.000 1.0</DIV>
<DIV>> 0.333 0.333 0.000 1.0</DIV>
<DIV>> 0.500 0.000 0.000 1.0</DIV>
<DIV>> S2.</DIV>
<DIV>> K_POINTS</DIV>
<DIV>> 3</DIV>
<DIV>> 0.0 0.0 0.0 1</DIV>
<DIV>> -0.333 0.667 0.000 1</DIV>
<DIV>> 0.000 0.500 0.000 1</DIV>
<DIV>></DIV>
<DIV>> S1 leads to the following energy band:</DIV>
<DIV>> k = 0.0000 0.0000 0.0000 ( 1139 PWs) bands (ev):</DIV>
<DIV>> -17.6202 -7.0494 -4.2017 -4.2017 -0.4467 1.5150 1.6453 2.3677</DIV>
<DIV>> k = 0.3330 0.3330 0.0000 ( 1095 PWs) bands (ev):</DIV>
<DIV>> -15.2584 -10.1839 -6.6316 -4.3186 0.2328 1.6659 3.8224 4.8909</DIV>
<DIV>> k = 0.5000 0.0000 0.0000 ( 1096 PWs) bands (ev):</DIV>
<DIV>> -15.1008 -10.7511 -5.7976 -4.1069 -0.3499 0.3805 4.1445 5.3833</DIV>
<DIV>> highest occupied, lowest unoccupied level (ev): -4.1069 -0.4467</DIV>
<DIV>> however, S2 leads to:</DIV>
<DIV>> k = 0.0000 0.0000 0.0000 ( 1139 PWs) bands (ev):</DIV>
<DIV>> -17.7480 -7.1365 -4.3482 -4.3482 -0.5055 1.5128 1.6485 2.3416</DIV>
<DIV>> k =-0.3330 0.6670 0.0000 ( 1092 PWs) bands (ev):</DIV>
<DIV>> -15.8503 -9.8006 -5.8672 -4.9789 0.6816 0.8106 3.0639 4.2245</DIV>
<DIV>> k = 0.0000 0.5000 0.0000 ( 1102 PWs) bands (ev):</DIV>
<DIV>> -15.1554 -10.1200 -7.9378 -4.0954 0.0949 3.2276 4.3675 4.3703</DIV>
<DIV>> highest occupied, lowest unoccupied level (ev): -4.0954 -0.5055</DIV>
<DIV>></DIV>
<DIV>> The differences between two results seem to be large.</DIV>
<DIV>> The differences between two jobs are only the setting of k-points.</DIV>
<DIV>> The input file is as follow:</DIV>
<DIV>> *********************************************</DIV>
<DIV>> &control</DIV>
<DIV>> calculation='scf'</DIV>
<DIV>> restart_mode='from_scratch',</DIV>
<DIV>> prefix='SiC111'</DIV>
<DIV>> /</DIV>
<DIV>> &system</DIV>
<DIV>> ibrav=0,nat=2,ntyp=2</DIV>
<DIV>> ecutwfc = 15.0, occupations='fixed'</DIV>
<DIV>> nbnd=8</DIV>
<DIV>> /</DIV>
<DIV>> &electrons</DIV>
<DIV>> diagonalization='david',</DIV>
<DIV>> conv_thr = 1.0d-10,</DIV>
<DIV>> mixing_beta = 0.5,</DIV>
<DIV>> startingwfc='random',</DIV>
<DIV>> /</DIV>
<DIV>> ATOMIC_SPECIES</DIV>
<DIV>> Si 28.06 Si.pbe-mt_gipaw.UPF</DIV>
<DIV>> C 12.01 C.pbe-mt_gipaw.UPF</DIV>
<DIV>> K_POINTS</DIV>
<DIV>> 3</DIV>
<DIV>> 0.000 0.000 0.000 1.0</DIV>
<DIV>> 0.333 0.333 0.000 1.0</DIV>
<DIV>> 0.500 0.000 0.000 1.0</DIV>
<DIV>></DIV>
<DIV>> CELL_PARAMETERS (angstrom)</DIV>
<DIV>> 2.6844596 -1.5498735 0.0000000</DIV>
<DIV>> 0.0000000 3.0997470 0.0000000</DIV>
<DIV>> 0.0000000 0.0000000 20.0077731</DIV>
<DIV>> ATOMIC_POSITIONS (crystal)</DIV>
<DIV>> C 0.000000 0.000000 0.500000</DIV>
<DIV>> Si 0.333333 -0.333333 0.500000</DIV>
<DIV>> *********************************************</DIV>
<DIV>></DIV>
<DIV>></DIV>
<DIV>> Any help will be appreciated.</DIV>
<DIV>></DIV>
<DIV>> Youzhao Lan</DIV>
<DIV>> Zhejiang Normal University,</DIV>
<DIV>> China.</DIV>
<DIV>> --------------------------------------------------------</DIV>
<DIV>></DIV>
<DIV>></DIV>
<DIV>></DIV>
<DIV>></DIV>
<DIV>></DIV>
<DIV>></DIV>
<DIV>> ________________________________</DIV>
<DIV>> 2016-05-29 12:42:52</DIV>
<DIV>></DIV>
<DIV>> _______________________________________________</DIV>
<DIV>> Pw_forum mailing list</DIV>
<DIV>> Pw_forum@pwscf.org</DIV>
<DIV>> http://pwscf.org/mailman/listinfo/pw_forum</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>-- </DIV>
<DIV>Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,</DIV>
<DIV>Univ. Udine, via delle Scienze 208, 33100 Udine, Italy</DIV>
<DIV>Phone +39-0432-558216, fax +39-0432-558222</DIV>
<DIV>_______________________________________________</DIV>
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