It is in the second mail in this thread. Mr. Lorenzo Paulatto said the problem may be because the unit cell is too small.
On Wed, Dec 14, 2016 at 7:45 PM, Paolo Giannozzi <[email protected]> wrote: > On Wed, Dec 14, 2016 at 3:00 PM, sayan chaudhuri <[email protected]> > wrote: > > > How to get rid of the small unit cell problem? > > what is the "small unit cell problem"? > > Paolo > > When it is a pure system, Wycoff positions with Atomic positions card > set > > at alat works. So, is there any definite procedure to give the position > of > > the atoms in the system when I am doping in the system? > > > > Thanking you, > > Sayan Chaudhuri > > > > On Fri, Dec 9, 2016 at 7:07 PM, Lorenzo Paulatto > > <[email protected]> wrote: > >> > >> It may be difficult to converge LDA+U calculations in general, starting > >> with > >> initial magnetizations that aren't absurd may help > >> > >> hth > >> > >> On Friday, December 9, 2016 5:29:01 PM CET Максим Арсентьев wrote: > >> > Dear Lorenzo, > >> > > >> > I have the same problem - cannot achieve SCF convergence. I use higher > >> > ecutwfc = 39.0, ecutrho = 300 but not coverging. > >> > > >> > Regards, Maxim Arsentev. > >> > > >> > 2016-12-09 12:52 GMT+04:00 Lorenzo Paulatto > >> > <[email protected]> > >> > > Dear Sayan, > >> > > it looks to me like your unit cell is too small, the atoms are all > >> > > crumped > >> > > together. Please note that celldm(1) is specified in bohr atomic > >> > > units. > >> > > > >> > > Also: > >> > > 1. a cutoff of 30Ry is probably very small for BHS pseudopotentials > >> > > 2. ecutrho=default (4*ecutwfc ) is probably not enough for all the > >> > > ultrasoft > >> > > pseudopotentials you are using > >> > > > >> > > I would recommend you first spend some time reproducin the > >> > > single-element > >> > > metal, and once you can correctly reproduce geometry, band > structure, > >> > > physical > >> > > properties, you move to simulating the alloy. > >> > > > >> > > HTH > >> > > > >> > > On Friday, December 9, 2016 1:59:44 PM CET sayan chaudhuri wrote: > >> > > > Hi, > >> > > > > >> > > > I am running QE self - consistently for my heusler > alloy(Fe2TiSn) > >> > > > > >> > > > system, where 25% of Sn were replaced by Sb. But after 800 > >> > > > iterations > >> > > > and > >> > > > almost 3 hours of running also still it is not converged. > >> > > > The code I am using is added bellow. Please tell me what is the > >> > > > source > >> > > > of > >> > > > error. > >> > > > > >> > > > Thanking you, > >> > > > > >> > > > Sayan Chaudhuri > >> > > > > >> > > > *&control prefix='fts', calculation = 'scf', verbosity = > >> > > > 'low', pseudo_dir = '/home/ltp/Desktop/espresso-5. > 4.0/pseudo', > >> > > > outdir = './tmp', / &system ibrav=2 celldm(1)=11.43, > >> > > > nat=16, ntyp=4, nspin=2, ecutwfc=30.0, > >> > > > starting_magnetization(1) = 0.0, starting_magnetization(2) = > >> > > > 0.0, > >> > > > starting_magnetization(3) = 0.5, starting_magnetization(3) = > >> > > > 0.0, > >> > > > occupations='tetrahedra', / &electrons electron_maxstep = > >> > > > 3000, > >> > > > diagonalization = 'david', mixing_mode = 'plain', conv_thr = > >> > > > 1e-8, > >> > > > mixing_beta=0.1, /ATOMIC_SPECIES Sb 121.76 Sb.pz-bhs.UPF Sn > >> > > > 118.71 Sn.pz-dn-rrkjus_psl.0.2.UPF Fe 55.845 > >> > > > Fe.pz-sp-van_ak.UPF > >> > > > Ti 47.867 Ti.pz-sp-van.UPFATOMIC_POSITIONS {crystal} Sb > >> > > > 0.000000000 0.000000000 0.000000000 Sn > >> > > > 0.000000000 0.500000000 0.500000000 Sn > >> > > > 0.500000000 0.000000000 0.500000000 Sb > >> > > > 0.500000000 0.500000000 0.000000000 Fe > >> > > > 0.250000000 0.250000000 0.250000000 Fe > >> > > > 0.750000000 0.750000000 0.750000000 Fe > >> > > > 0.750000000 0.750000000 0.250000000 Fe > >> > > > 0.250000000 0.250000000 0.750000000 Fe > >> > > > 0.750000000 0.250000000 0.750000000 Fe > >> > > > 0.250000000 0.750000000 0.250000000 Fe > >> > > > 0.250000000 0.750000000 0.750000000 Fe > >> > > > 0.750000000 0.250000000 0.250000000 Ti > >> > > > 0.500000000 0.500000000 0.500000000 Ti > >> > > > 0.500000000 0.000000000 0.000000000 Ti > >> > > > 0.000000000 0.500000000 0.000000000 Ti > >> > > > 0.000000000 0.000000000 0.500000000 K_POINTS > >> > > > {automatic} > >> > > > 2 2 2 0 0 0* > >> > > > >> > > -- > >> > > Dr. Lorenzo Paulatto > >> > > IdR @ IMPMC -- CNRS & Université Paris 6 > >> > > phone: +33 (0)1 44275 084 / skype: paulatz > >> > > www: http://www-int.impmc.upmc.fr/~paulatto/ > >> > > mail: 23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris > >> > > Cédex 05 > >> > > > >> > > _______________________________________________ > >> > > Pw_forum mailing list > >> > > [email protected] > >> > > http://pwscf.org/mailman/listinfo/pw_forum > >> > >> > >> -- > >> Dr. Lorenzo Paulatto > >> IdR @ IMPMC -- CNRS & Université Paris 6 > >> phone: +33 (0)1 44275 084 / skype: paulatz > >> www: http://www-int.impmc.upmc.fr/~paulatto/ > >> mail: 23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex > 05 > >> > >> _______________________________________________ > >> Pw_forum mailing list > >> [email protected] > >> http://pwscf.org/mailman/listinfo/pw_forum > > > > > > > > _______________________________________________ > > Pw_forum mailing list > > [email protected] > > http://pwscf.org/mailman/listinfo/pw_forum > > > > -- > Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, > Univ. Udine, via delle Scienze 208, 33100 Udine, Italy > Phone +39-0432-558216, fax +39-0432-558222 > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum >
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