So, no one has any idea?
Chao Cao wrote: > Dear PWSCF users and developers: > > I have been trying to use PWSCF's implementation of LDA+U to calculate > the electronic structure of CaCuO2 lately. In VASP, once I turn on U, it > gives AFM ground state and reasonable gap separation at E_F. However, > the procedure seems to be much harder for PWSCF. While it gets AFM gs > correctly, I can never get a band gap. I searched the forum, and I > realized that the initial occupation number might be important, but the > several combinations I tried seem to give me the same result. So, is > there any hint or suggestions, especially how to choose initial > occupation numbers? Thanks in advance. > > > Best, > > Chao Cao > > > And, here's my input file: > > &control > calculation = 'scf' > restart_mode = 'from_scratch' > prefix = 'CaCuO2' > disk_io = 'low' > outdir = './' > / > &system > ibrav = 0, celldm(1) = 1.88972688, ntyp = 4, nat = 16 > nbnd=80, ecutwfc = 32, ecutrho = 400 > nspin = 2, starting_magnetization(2)=0.5, starting_magnetization(3)=-0.5 > lda_plus_u = .true., Hubbard_U(2) = 6.5, Hubbard_U(3) = 6.5 > occupations = 'smearing', smearing = 'mp', degauss = 0.007 > / > &electrons > mixing_beta = 0.2 > conv_thr = 1.0d-9 > / > ATOMIC_SPECIES > Ca 1.0 Ca.pbe-nsp-van.UPF > Cuu 1.0 Cu.pbe-n-van.UPF > Cud 1.0 Cu.pbe-n-van.UPF > O 1.0 O.pbe-van.UPF > ATOMIC_POSITIONS crystal > Ca 0.25 0.75 0.25 > Ca 0.75 0.25 0.25 > Ca 0.25 0.75 0.75 > Ca 0.75 0.25 0.75 > Cuu 0.25 0.25 0.00 > Cuu 0.75 0.75 0.50 > Cud 0.75 0.75 0.00 > Cud 0.25 0.25 0.50 > O 0.00 0.00 0.00 > O 0.50 0.00 0.00 > O 0.00 0.50 0.00 > O 0.50 0.50 0.00 > O 0.00 0.00 0.50 > O 0.50 0.00 0.50 > O 0.00 0.50 0.50 > O 0.50 0.50 0.50 > K_POINTS automatic > 8,8,4,1,1,1 > CELL_PARAMETERS cubic > 3.878393250 3.878393249 0.000000000 > -3.878393249 3.878393250 0.000000000 > 0.000000000 0.000000000 6.409031058 > > > > > -- Chao Cao Quantum Theory Project and Department of Physics University of Florida, Gainesville, FL 32611 U.S.A.
