Dear all, I have been working on bismuth ferrite BiFeO3, from past few months. I use NC pseudopotential from pseudodojo and made all the optimization with respect to cutoff energy, K-points before performing the calculations. The band calculation shows no bandgap (it has a bandgap of about 2.67 eV), hence calculations like Berry phase, dielectric and Turbo Lanczos and others cannot be performed as it is predicted to be a metal. I solved the bandgap issue with the implementation of Hubbard potential (up to U= 5 eV for Fe), but this does not solve the issue completely as few of the calculations do not have the implementation of Hubbard potential in them. I wanted to know whether I am making any mistake or is there any workaround so that I can perform the dielectric property calculations for my material. I am pasting the scf input file if it is of any use. Thanks in advance
/* Input file*/ &CONTROL calculation = "scf" restart_mode = 'from _scratch" max_seconds = 8.64000e+04 pseudo_dir = "." tprnfor = .TRUE. prefix = "BFO" outdir = "./outdir" tstress = .TRUE. / &SYSTEM a = 5.645 cosab = 0.50000 degauss = 1.00000e-02 ecutrho = 9.60000e+02 ecutwfc = 8.00000e+01 ibrav = 5 nat = 10 nspin = 2 ntyp = 3 lda_plus_u =.true Hubbard_U(1) =2.0 occupations = "smearing" smearing = "gaussian" starting_magnetization(1) = 2.00000e-01 starting_magnetization(2) = 0.00000e+00 starting_magnetization(3) = 0.00000e+00 / &ELECTRONS conv_thr = 1.00000e-09 electron_maxstep = 200 mixing_beta = 4.00000e-01 startingpot = "atomic" startingwfc = "atomic+random" / K_POINTS {automatic} 8 8 8 0 0 0 ATOMIC_SPECIES Fe 55.84500 Fe.UPF Bi 208.98038 Bi.UPF O 15.99940 O.UPF ATOMIC_POSITIONS (crystal) Fe 0.777130455 0.777130455 0.777130455 Fe 0.277129455 0.277129455 0.277129455 Bi 0.509340660 0.509340660 0.509340660 Bi 0.009340660 0.009340660 0.009340660 O 0.563857130 0.956239313 0.116400442 O 0.956239313 0.116400442 0.563857130 O 0.116400442 0.563857130 0.956239313 O 0.616401442 0.456238313 0.063856130 O 0.456238313 0.063856130 0.616401442 O 0.063856130 0.616401442 0.456238313 /* end of input file */ Regards, Srihari Research scholar Department of Physics Manipal Institute of Technology Manipal
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