Thank you so much Vahid. I have a question though..how did you get the initial CELL_PARAMETERS ? I obtained the initial cell and atomic parameters from bulk.
GAUTAM GADDEMANE DEPARTMENT OF MATERIALS SCIENCE AND ENGINEERING UNIVERSITY OF TEXAS AT DALLAS On Thu, Oct 5, 2017 at 4:19 PM, Vahid Askarpour <vh261...@dal.ca> wrote: > Hi Gautam, > > The following relaxation input worked for me: > > BP > 2D > &control > calculation='vc-relax' > restart_mode='from_scratch', > prefix='BP' > pseudo_dir='./' > verbosity='high' > tprnfor=.true. > tstress=.true. > etot_conv_thr=1.0e-06 > forc_conv_thr=1.0e-05 > / > &system > ibrav=0, > nat= 4, ntyp= 1 > ecutwfc = 50, ecutrho=200, > occupations = 'fixed' , > / > &electrons > diagonalization='cg' > conv_thr = 1.0e-12 > mixing_beta = 0.7 > electron_maxstep = 500 > mixing_mode = 'plain' > / > &IONS > ion_dynamics = 'bfgs' > pot_extrapolation='atomic' > wfc_extrapolation='atomic' > / > &CELL > cell_dynamics = 'bfgs' > wmass=0.002 > cell_factor=2.0 > cell_dofree='xyz' > / > ATOMIC_SPECIES > P 30.97376 P.pbesol-n-kjpaw_psl.0.1.UPF > > K_POINTS {automatic} > 14 12 1 0 0 0 > > CELL_PARAMETERS (angstrom) > 4.429539231 0.000000000 0.000000000 > 0.000000000 3.279402120 0.000000000 > 0.000000000 0.000000000 31.941846246 > > ATOMIC_POSITIONS (crystal) > P 0.001152971 0.000000000 0.015264978 > P 0.335395312 0.499999800 0.015264292 > P 0.501101273 0.499999800 0.081335135 > P 0.835350444 0.000000000 0.081335495 > > Best, > > Vahid > > Vahid Askarpour > Department of Physics and Atmospheric Science > Dalhousie University, > Halifax, NS, Canada > > > On Oct 5, 2017, at 4:45 PM, Gautam Gaddemane <gautam...@gmail.com> > wrote: > > > > Dear All, > > > > I am trying to calculate the bands tructure for monolayer phosphorene > and I am just a week old in using quantum espresso. > > From the bulk unit cell I prepared an input file to relax the structure > but I was not able to get a good lattice constant nor a good band gap. It > would be very helpful if someone would guide me in this procedure. > > I have attahced the file I used to relax in this email > > > > > > &CONTROL > > calculation='vc-relax', > > outdir='./', > > prefix='calc', > > pseudo_dir='./', > > verbosity='high', > > / > > > > &SYSTEM > > ibrav=0, > > celldm(1)= 8.276999830d0 > > nat=4, > > ntyp=1, > > ecutwfc=60, > > ecutrho=360, > > input_dft='lda', > > occupations='smearing', > > smearing='mv', > > degauss=0.005d0, > > / > > > > &ELECTRONS > > conv_thr=1d-06, > > mixing_beta=0.7d0, > > / > > &IONS > > ion_dynamics='bfgs' > > / > > > > &CELL > > cell_dynamics='bfgs' > > cell_dofree='2Dshape' > > / > > ATOMIC_SPECIES > > P 30.973800d0 P.pw-mt_fhi.UPF > > > > ATOMIC_POSITIONS {crystal} > > > > P 0.090000004 0.000000000 0.050195117 > > P 0.909999967 0.000000000 0.949804902 > > P 0.590000033 0.500000000 0.949804902 > > P 0.409999996 0.500000000 0.050195117 > > > > K_POINTS {automatic} > > > > 12 12 1 0 0 0 > > > > CELL_PARAMETERS {alat} > > > > 1.0000000000000000 0.0000000000000000 0.0000000000000000 > > 0.0000000000000000 0.7511415530000000 0.0000000000000000 > > 0.0000000000000000 0.0000000000000000 4.68036529200000000 > > > > > > thank you > > Gautam > > > > GAUTAM GADDEMANE > > DEPARTMENT OF MATERIALS SCIENCE AND ENGINEERING > > UNIVERSITY OF TEXAS AT DALLAS > > _______________________________________________ > > Pw_forum mailing list > > Pw_forum@pwscf.org > > http://pwscf.org/mailman/listinfo/pw_forum > > > _______________________________________________ > Pw_forum mailing list > Pw_forum@pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum >
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