[Pw_forum] Atomic positions of atoms in hybrid perovskite CH3NH3PbI3 ?

[Christoph Wolf]

Quite hard to say with the naked eye...

A few suggestions: 

1) get a structure file (cif) file from a repository (crystallography.info
etc) and convert it to an QE input file using the script cif2cell with the
option -p quantum-espresso
2) check structure files published by other groups (I think
https://github.com/WMD-group/hybrid-perovskites had plenty of); it is easy
to convert the crystal structure to QE format
...
Finally, check how it looks by xcrysden (xcrysden --pwi input_file_name);
set the correct unit cell repetition to avoid overlapping periodic cells;

PS: for MAPbI3 (and all related) spin-orbit coupling plays a large role in
the band-structure

HTH

Chris 

Message: 10
Date: Wed, 1 Mar 2017 14:35:37 +0530
From: Saurabh Kumar <saurabhkumar651994 at gmail.com>
Subject: [Pw_forum] Atomic positions of atoms in hybrid perovskite
	CH3NH3PbI3 ?
To: pw_forum at pwscf.org
Message-ID:
	<CAFiy4VhsQaL6erZ=bV3zoe=RKskzsucUjT9efpT1SKW8cLw+vQ at mail.gmail.com>
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Dear All,

    I am trying to calculate band structure of hybrid perovskite CH3NH3PbI3.

please suggest me the atomic position of atoms in hybrid perovskite
CH3NH3PbI3.

     I make a file for hybrid perovskite CH3NH3PbI3.


 &CONTROL
                 calculation = 'scf' ,
                      outdir = 'CH3NH3PbCl3' ,
                  pseudo_dir = '.' ,
                      prefix = 'calc' ,
                   verbosity = 'low' ,
                     tstress = .false. ,
                     tprnfor = .false. ,
 /
 &SYSTEM
                       ibrav = 6,
                     celldm(1) = 16.772175819192d0,
                     celldm(3) = 1.427919554d0,
                         nat = 48,
                        ntyp = 5,
                     ecutwfc = 30 ,
                     ecutrho = 300 ,
                   input_dft = 'lda' ,

 /
 &ELECTRONS
                    conv_thr = 1d-06 ,
                 mixing_mode = 'plain' ,
                 mixing_beta = 0.700d0 ,
             diagonalization = 'david' ,
 /
ATOMIC_SPECIES
   Cl   35.45300  Cl.pz-n-rrkjus_psl.0.1.UPF
   Pb  207.20000  Pb.pz-dn-rrkjus_psl.0.2.2.UPF
    C   12.01000  C.pz-n-rrkjus_psl.0.1.UPF
    N   14.00670  N.pz-n-rrkjus_psl.0.1.UPF
    H    1.00794  H.pz-rrkjus_psl.0.1.UPF
ATOMIC_POSITIONS {crystal}
   Pb      0.937020143   -1.381620552    2.098848798
   Cl      3.211929739    0.317599239    1.844273817
   Cl      2.699872755    1.301845443   -3.305788426
   Pb      0.964431461   -1.008900183   -3.532207636
   Cl     -0.489754419   -3.511397613   -3.633088932
   Cl      1.034885395   -1.534215680   -0.759835038
   Cl      1.409893953   -1.285797523    4.938867114
   Cl     -1.132155996    0.537298685    2.399452065
   Pb     -3.080944681    2.580388321    2.231991058
   Cl     -3.279652103    3.073405815    5.085611211
   Cl      2.703232904   -3.640473759    2.225540867
   Cl      3.347432086   -2.614462807   -3.350845770
   Cl     -1.134693736   -3.338622116    2.539171237
   Cl     -1.378510211    0.684905164   -3.215713026
   Pb     -2.973784309    3.022014726   -3.468219920
   Cl     -3.189002236    2.822985615   -0.579682726
    C      1.011249439    2.100007146    4.846637634
    N      0.768103727    3.569701583    4.900244063
    H      1.391401901    1.843649875    3.850768134
    H      1.746556583    1.834665268    5.616021108
    H      0.062189194    1.581313485    5.022904990
    H      0.406354704    3.873014073    5.836799757
    H      1.632027238    4.102254012    4.702229080
    H      0.072765972    3.875031075    4.176030363
    C      5.346104178   -0.892597492    5.376031513
    N      4.556882827   -1.662165641    4.369176663
    H      5.057137431   -1.239196765    6.374216016
    H      6.413413086   -1.069268376    5.196888416
    H      5.117813950    0.175515396    5.266776856
    H      4.771458453   -1.350482932    3.407072251
    H      4.746496105   -2.685664408    4.434941757
    H      3.528634541   -1.528108529    4.524757283
    C      0.602056880    2.494670338   -0.198488995
    N      1.599120434    3.253212641   -1.010040233
    N      4.494548212   -0.640988937   -1.050826182
    C      5.452038014   -1.591220629   -0.416658882
    H      1.019923491    1.507847799    0.035942296
    H      0.405831256    3.047246714    0.727770443
    H     -0.320919033    2.386376409   -0.780236952
    H      1.299347740    4.237973746   -1.174416380
    H      2.528500760    3.284664511   -0.540992123
    H      1.765769882    2.779408882   -1.926239918
    H      4.889643075   -2.438266266   -0.008625119
    H      6.159405961   -1.941750558   -1.177483464
    H      5.987760207   -1.066352016    0.382960466
    H      5.004402403    0.128660156   -1.526288120
    H      3.934931011   -1.136283995   -1.781604973
    H      3.860276085   -0.233082640   -0.332648827
K_POINTS {automatic}
  8 8 8   0 0 0


  is this correct or not?

       Best wishes .