You can only use lspinorbit=.true. if you have a relativistic pseudo which not the case of my pseudo... In any case I do not think spin-orbit coupling will change very much your bulk modulus. SOC is just a tiny effect on total energy, at least for 3d metals...
The most important thing is that you describe properly the AF state. Why do you initialize the magnetization with starting_magnetization(1)=0.7, starting_magnetization(2)=-0.4, breaking the symmetry between the two atoms. Furthermore you have declared only one type of atoms while you have two types.. I guess you will endup with the non-magnetic solution in your case.. You should declare ntype=2 and starting_magnetization(1)=0.3, starting_magnetization(2)=-0.3, hth cyrille ----------------------------------------------------------------------------------------------------------- Cyrille Barreteau CEA Saclay, IRAMIS, SPCSI, Bat. 462 91191 Gif sur Yvette Cedex, FRANCE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ phone: +33 (0)1 69 08 29 51 / +33 (0)6 47 53 66 52 fax : +33 (0)1 69 08 84 46 email: cyrille.barreteau at cea.fr Web: http://iramis.cea.fr/Pisp/cyrille.barreteau/ ----------------------------------------------------------------------------------------------------------- ________________________________________ De : pw_forum-bounces at pwscf.org [pw_forum-bounces at pwscf.org] de la part de Ben Palmer [benpalmer1983 at gmail.com] Date d'envoi : jeudi 6 juin 2013 18:27 ? : PWSCF Forum Objet : [Pw_forum] Noncolin vs Nspin=1 for Chromium Hi Everyone, I've been using a few of the supplied PPs and one kindly suggested/sent to me by Derek/Cyrille. I've used these to try to calculate the bulk modulus. First, I used nspin = 1 and with the latest PP ended with a bulk modulus of 268GPa. I then repeated with noncolin=.true. and lspinorb=.true. and I was expecting a different result, but at the end it gave me 268GPa again. I was just wondering whether I'd missed something in my input script, or whether I'd made any obvious errors? This is one of my nspin=1 input files: &CONTROL restart_mode='from_scratch', calculation=scf, etot_conv_thr=1.0E-7, forc_conv_thr=1.0D-6, nstep=200, prefix="7ca5bad5d48c", pseudo_dir="/gpfs/bb/bxp912/pseudopotentials/", outdir="/gpfs/bb/bxp912/scratch/", / &SYSTEM ibrav=14, celldm(1)=5.36800113, celldm(2)=1, celldm(3)=1, celldm(4)=0, celldm(5)=0, celldm(6)=0, nat=2, ntyp=1, ecutwfc=600, ecutrho=2400, occupations='smearing', smearing='mv', degauss=0.1, / &ELECTRONS diagonalization='david', mixing_mode='plain', mixing_beta=0.7, conv_thr=1.0D-7, / &IONS ion_dynamics='bfgs', / &CELL cell_dynamics='bfgs', press=0.0, cell_factor=2.0, / ATOMIC_SPECIES Cr 51.9961 Cr.pbe-us_norel_cyrille.UPF ATOMIC_POSITIONS crystal Cr 0.0000000000 0.0000000000 0.0000000000 Cr 0.5000000000 0.5000000000 0.5000000000 K_POINTS automatic 8 8 8 1 1 1 And this is one of my noncolin input files: &CONTROL restart_mode='from_scratch', calculation=scf, etot_conv_thr=1.0E-7, forc_conv_thr=1.0D-6, nstep=200, prefix="c7700ccaacf", pseudo_dir="/gpfs/bb/bxp912/pseudopotentials/", outdir="/gpfs/bb/bxp912/scratch/", / &SYSTEM ibrav=14, celldm(1)=5.4753116928, celldm(2)=1, celldm(3)=1, celldm(4)=0, celldm(5)=0, celldm(6)=0, nat=2, ntyp=1, ecutwfc=400, ecutrho=1200, occupations='smearing', smearing='mv', degauss=0.1, noncolin=.true., lspinorb=.true., starting_magnetization(1)=0.7, starting_magnetization(2)=-0.4, / &ELECTRONS diagonalization='david', mixing_mode='plain', mixing_beta=0.7, conv_thr=1.0D-7, / &IONS ion_dynamics='bfgs', / &CELL cell_dynamics='bfgs', press=0.0, cell_factor=2.0, / ATOMIC_SPECIES Cr 51.9961 Cr.pbe-us_norel_cyrille.UPF ATOMIC_POSITIONS crystal Cr 0.0000000000 0.0000000000 0.0000000000 Cr 0.5000000000 0.5000000000 0.5000000000 K_POINTS automatic 8 8 8 1 1 1 All the best, Ben _______________________________________________ Pw_forum mailing list Pw_forum at pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
