Dear Suza It seems like BaTiO3 is not a simple cubic structure, so you should
not choose ibrav=1. Chengyang ----- Original Message -----
> From: "Suza W" <suza.rri at gmail.com>
> To: "PWSCF Forum" <pw_forum at pwscf.org>
> Sent: Wednesday, November 30, 2011 3:32:15 PM
> Subject: [Pw_forum] DC & BEC
> Dear All,
> Being an epitome of ferroelectric, BaTiO3 has extensively been
> studied using PWSCF. However,? unfortunately, with several
> standard available USPP, I encounter? following unphysical? results :?
> ???????
> ???? Dielectric constant in cartesian axis
> ????????? (-8142842.391767483?????? 0.000000000?????? 0.000000000 )
> ????????? (?????? 0.000000000-8142842.391767481?????? 0.000000000 )
> ????????? (?????? 0.000000000?????? 0.000000000-8142842.391767476 )
> ????????? Effective charges (d Force / dE) in cartesian axis
> ?????????? atom????? 1?? Ba
> ????? Ex? (??? -1136.43937??????? 0.00000??????? 0.00000 )
> ????? Ey? (??????? 0.00000??? -1136.43937??????? 0.00000 )
> ????? Ez? (??????? 0.00000??????? 0.00000??? -1136.43937 )
> ?????????? atom????? 2?? Ti
> ????? Ex? (??? -1874.03151??????? 0.00000??????? 0.00000 )
> ????? Ey? (??????? 0.00000??? -1874.03151??????? 0.00000 )
> ????? Ez? (??????? 0.00000??????? 0.00000??? -1874.03151 )
> ?????????? atom????? 3?? O?
> ????? Ex? (????? 931.42284??????? 0.00000??????? 0.00000 )
> ????? Ey? (??????? 0.00000???? 1067.39482??????? 0.00000 )
> ????? Ez? (??????? 0.00000??????? 0.00000???? 1067.39482 )
> ?????????? atom????? 4?? O?
> ????? Ex? (???? 1067.39482??????? 0.00000??????? 0.00000 )
> ????? Ey? (??????? 0.00000????? 931.42284??????? 0.00000 )
> ????? Ez? (??????? 0.00000??????? 0.00000???? 1067.39482 )
> ?????????? atom????? 5?? O?
> ????? Ex? (???? 1067.39482??????? 0.00000??????? 0.00000 )
> ????? Ey? (??????? 0.00000???? 1067.39482??????? 0.00000 )
> ????? Ez? (??????? 0.00000??????? 0.00000????? 931.42284 )
> Any suggestion for correcting these errors will be highly
> appreciated.?
> Here goes the input file which renders such a blunder.?
> ?&system
> ??? ibrav =? 1,
> ??? celldm(1) = 7.5589,
> ??? nat = 5,
> ??? ntyp=3,
> ??? ecutwfc = 30.0,
> ??????? ecutrho = 240.0,
> ?/
> ?&electrons
> ??? diagonalization = 'david'
> ??? conv_thr =? 1.0d-9
> ??? mixing_beta = 0.7
> ?/
> ?&ions
> ?/
> ?&cell
> ?/
> ATOMIC_SPECIES
> ?Ba? 137.327?????? Ba.pbe-nsp-van.UPF
> ?Ti?? 47.867?????? Ti.pbe-sp-van_ak.UPF
> ?O??? 15.9994????? O.pbe-van_ak.UPF
> ATOMIC_POSITIONS (alat)
> Ba? 0.0? 0.0? 0.0
> Ti? 0.5? 0.5? 0.5
> O? 0.0? 0.5? 0.5
> O? 0.5? 0.0? 0.5
> O? 0.5? 0.5? 0.0
> K_POINTS {automatic}
> ?8 8 8? 1 1 1
> Thanking you,
> Yours sincerely,
> Suza W
> PhD Student
> Department of Materials Science
> Bangalore
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