Menghao, Whereas I am not sure what exactly is the setup for the angles theta and phi (that is, if theta is measured from the z axis or from the x-y plane), it could be that theta=90 degrees is already a possible energy minimum. In particular, if theta is measured from the x-y plane, then you have your previous starting point, which is the spin aligned along the z axis. However, in spin-polarized calculations many different minima can exist, and it's up to you to try different configurations to find the global minimum.
If theta=90 deg is already an energy minimum for your system, then nothing will change. What happens if you set a different value for theta, say, a weird one like 26.73 degrees? Marcos 2011/1/26 吴梦昊 <[email protected]> > Hi, > Thank you for your advice. When I use %block DM.InitSpin to set > a initial spin, > I add: > %block DM.InitSpin > 7 + 90. 0. > %endblock DM.InitSpin > > > > it seems that the direction will be fixed at angle 90 during > optimization--- > the direction will not optimize itself. So in noncollinear calculation, we > have to compare energy of all sort of spin angle, and we cannot let > the spin direction optimized itself? Thank you and look forward to > advice > Sincerely > Menghao Wu > > > > 2011/1/23 Lucas Fernandez Seivane <[email protected]>: > > Hi > > > > Look for %block DM.InitSpin in the manual. You have to set magnetic > > seeds with that options. > > > > regards > > Lucas > > 2011/1/24 吴梦昊 <[email protected]>: > >> Dear siesta users and developers： > >> I found siesta results of noncollinear calculation always leads to > >> magnetization > >> only in z-direction-----even I switched the directin of magnet! Has > >> anyone else found > >> something wrong with noncollinear calculation? Or something > >> wrong with my operation? > >> I put fdf file below. > >> I appreciate your suggestions about this > >> problem. > >> > >> > >> With best regards > >> Menghao Wu > >> > >> > >> # Output options > >> > >> WriteCoorStep > >> WriteMullikenPop 1 > >> > >> # Species and atoms > >> > >> NumberOfSpecies 3 > >> NumberOfAtoms 13 > >> %block ChemicalSpeciesLabel > >> 1 6 C > >> 2 25 Mn > >> 3 1 H > >> %endblock ChemicalSpeciesLabel > >> > >> # Basis > >> > >> PAO.EnergyShift 50 meV > >> PAO.BasisSize DZP > >> > >> > >> LatticeConstant 1.00 Ang > >> > >> %block LatticeVectors > >> 16.0000000000000000 .0000000000000000 .0000000000000000 > >> .0000000000000000 16.0000000000000 .0000000000000000 > >> .0000000000000000 .0000000000000000 3.3700000000000000 > >> %endblock LatticeVectors > >> > >> KgridCutoff 15. Ang > >> > >> %block BandLines > >> 1 0.00000 0.000000 0.000000 \Gamma > >> 30 0.00000 0.000000 0.500000 X > >> %endblock BandLines > >> > >> xc.functional LDA # Exchange-correlation functional > >> xc.authors CA # Exchange-correlation version > >> > >> SpinPolarized true # Logical parameters are: yes or > no > >> NonCollinearSpin true > >> MeshCutoff 150. Ry # Mesh cutoff. real space mesh > >> > >> # SCF options > >> MaxSCFIterations 500 # Maximum number of SCF iter > >> DM.MixingWeight 0.1 # New DM amount for next SCF cycle > >> DM.Tolerance 1.d-3 # Tolerance in maximum difference > >> # between input and output DM > >> DM.UseSaveDM true # to use continuation files > >> DM.NumberPulay 3 > >> > >> SolutionMethod Diagon # OrderN or Diagon > >> ElectronicTemperature 25 K # Temp. for Fermi smearing > >> Diag.ParallelOverK no > >> # MD options > >> > >> MD.TypeOfRun cg # Type of dynamics: > >> MD.NumCGsteps 200 # Number of CG steps for > >> # coordinate optimization > >> MD.MaxCGDispl 0.2 Ang # Maximum atomic displacement > >> # in one CG step (Bohr) > >> MD.iMaxForceTol 0.05 eV/Ang # Tolerance in the maximum > >> # atomic force (Ry/Bohr) > >> > >> # Atomic coordinates > >> AtomicCoordinatesFormat Ang > >> %block AtomicCoordinatesAndAtomicSpecies > >> 5.984342432 3.596261950 1.908996404 1 > >> 4.723873840 4.285144890 1.902371284 1 > >> 4.684148487 5.724854135 1.895339145 1 > >> 7.203280667 4.354484130 1.901971703 1 > >> 7.163821550 5.794305040 1.894546280 1 > >> 5.903464827 6.482998694 1.943705236 1 > >> 5.944012009 5.038898651 0.232220326 2 > >> 6.014619027 2.505118673 1.903154742 3 > >> 8.166882755 3.841390919 1.895707998 3 > >> 3.791368128 3.717187433 1.896437188 3 > >> 5.873242219 7.573943296 1.950529321 3 > >> 8.095885216 6.362797445 1.893455905 3 > >> 3.720974178 6.238472443 1.894629706 3 > >> %endblock AtomicCoordinatesAndAtomicSpecies > >> > >> > >> The result always has net M in z-direction: > >> Total Total 21.13603 2.63240 0.000 0.000 1.491 > >> > >> > >> even after I switch the direction of lattice to y-axis > >> %block LatticeVectors > >> 16.0000000000000000 .0000000000000000 .0000000000000000 > >> .0000000000000000 3.3700000000000 .0000000000000000 > >> .0000000000000000 .0000000000000000 16.00000000000000 > >> %endblock LatticeVectors > >> > >> # Atomic coordinates > >> AtomicCoordinatesFormat Ang > >> %block AtomicCoordinatesAndAtomicSpecies > >> 5.984342432 1.908996404 3.596261950 1 > >> 4.723873840 1.902371284 4.285144890 1 > >> 4.684148487 1.895339145 5.724854135 1 > >> 7.203280667 1.901971703 4.354484130 1 > >> 7.163821550 1.894546280 5.794305040 1 > >> 5.903464827 1.943705236 6.482998694 1 > >> 5.944012009 0.232220326 5.038898651 2 > >> 6.014619027 1.903154742 2.505118673 3 > >> 8.166882755 1.895707998 3.841390919 3 > >> 3.791368128 1.896437188 3.717187433 3 > >> 5.873242219 1.950529321 7.573943296 3 > >> 8.095885216 1.893455905 6.362797445 3 > >> 3.720974178 1.894629706 6.238472443 3 > >> %endblock AtomicCoordinatesAndAtomicSpecies > >> > > > > > > > > -- > > Lucas Fernández Seivane > > Ph. D. Candidate > > Universidad de Oviedo - CINN > > http://condmat.uniovi.es/~quevedin > > http://www.researcherid.com/rid/A-8610-2008 > > >
