Dear all Could anyone gave me some suggestion to do the constraint magnetic moment calculation? I followed the constraint magnetic moment calculation of the following handson with PWSCF. http://www.vasp.at/vasp-workshop/slides/handsonIV.pdf VASP uses the same method of PWSCF on constraint MM. However, I found the constraint energy is difficult to go zero. In the handson, they use lambda=50eV, got a constraint energy of 0.22591E-03eV. I used lambda=150Ry, but got a constraint energy=0.35Ry. Even PWSCF is different with VASP on some detail, I think it is not reasonable for two codes showing so large difference. So could anyone point the unreasonable part of my input file? Or give me some suggestion? This puzzled me for quite a long time. The following is the input file. &system ibrav= 0, nat= 2, ntyp= 2, ecutwfc = 80.0, occupations='smearing', degauss=0.001, smearing='gauss' starting_magnetization(1)=2.5 starting_magnetization(2)=2.5 angle1(1)=0.0 angle1(2)=45.0 angle2(1)=0.0 angle2(2)=90.0 constrained_magnetization="atomic direction" noncolin=.ture. lambda=150.0 nosym=.true. / &electrons mixing_beta = 0.1 electron_maxstep=200 startingwfc='file' startingpot='file' / ATOMIC_SPECIES Fe1 56 Fe.pbe-spn-kjpaw_psl.0.2.1.UPF Fe2 56 Fe.pbe-spn-kjpaw_psl.0.2.1.UPF ATOMIC_POSITIONS angstrom Fe1 3.0 0.0 0.0 Fe2 5.0 0.0 0.0 K_POINTS automatic 1 1 1 0 0 0 CELL_PARAMETERS angstrom 8.0 0.0000000000000000 0.0000000000000000 0.0 8.0 0.0000000000000000 0.0 0.0 8.0
PS1: I found the PWSCF used starting_magnetization as magnetization/charge for generating initial wave function,but used it as magnetization in constraint MM. So I set 2.5 for them. PS2: The startingwfc is of a smaller lambda calculation. -- PostDoc Department of Physics, South University of Science and Technology of China
