[QE-users] Proper scf input file for study SOC effect on magnetic insulator

[Nuttachai Jutong]

Dear Users, and developers,
I am using quantum espresso version 7.0 to study the SOC effect on
magnetic insulator (EuO) band structure.
I have no problem with the magnetic insulator band structure
calculated using LDA+U (without SOC). The procedure I used is the same
as recommended on
https://gitlab.com/QEF/q-e/-/tree/3ec392ecee8a83958789d31be5737adac07974ba/HP/examples/example02

There are 1st run scf with occupied ="smearing", then 2nd run scf with
occupations = fixed  and total magnetization = 7, after that 3rd I
repeat 1st step. I got a very nice band structure.
However, for the magnetic insulators with   LDA+U and SOC, I am not
sure whether the procedure I used is correct or not. It is because in
general to calculate with SOC, the fully relativistic PS has to be
used. The total magnetization seems does not work for fully
relativistic PS. Do you have any suggestions? The scf input files are
shown below.

1st: 01.scf.EuO_primitive_PAW.1.in

&control
    calculation = 'scf',
    restart_mode='from_scratch',
    prefix='00_EuO.Primitive.SOC.PAW.O-nl',
    outdir = '/home/nuttachai/qe-7.0-ReleasePack/qe-7.0_parallel/01_Project_EuO_SOC/00_Primitive/02_PAW_FR_SOC/01.1_Eu-kjpaw_O-nl_SOC',
    pseudo_dir ='/home/nuttachai/qe-7.0-ReleasePack/qe-7.0_parallel/01_Project_EuO_SOC/00_Primitive/02_PAW_FR_SOC',
    verbosity = 'high',
 /
 &system
    ibrav=  0,
    celldm(1) =9.721,
    nat=  2,
    ntyp= 2,
    !nspin= 2,
    noncolin=.true.,
    lspinorb=.true.,
    starting_magnetization(1)=6.9,
    !constrained_magnetization= 'atomic',
    !occupations='fixed',
    !tot_magnetization = 7.0,
    occupations='smearing',
    smearing='mp',
    degauss=0.001,
    ecutwfc=125.0,
    ecutrho=750.0,
    !nbnd = 96,
    !lda_plus_u=.true.,
    !lda_plus_u_kind = 1,
    !Hubbard_U(1)   = 9.3, Hubbard_J(1,1) = 0.00, Hubbard_J(2,1) =
0.00, Hubbard_J(3,1) = 0.77,
    !Hubbard_U(2)=4.6 , Hubbard_J(1,2)=1.2,
 /
 &electrons
    electron_maxstep = 20000,
    diagonalization = 'david',
    mixing_mode = 'local-TF',
     mixing_beta = 0.05,
    conv_thr =  1.0d-7,
    ! startingpot = 'file',
    !startingwfc = 'file',
 /
CELL_PARAMETERS alat
 0.000  0.500  0.500
 0.500  0.000  0.500
 0.500  0.500  0.000
ATOMIC_SPECIES
Eu 151.964  Eu.rel-pbe-spdfn-kjpaw_psl.1.0.0.UPF,
O  15.999   O.rel-pbe-nl-kjpaw_psl.1.0.0.UPF,
ATOMIC_POSITIONS {crystal}
Eu  0.000 0.000 0.000
O    0.500 0.500 0.500
K_POINTS {automatic}
7 7 7 0 0 0
---------------------------------------------------------------
2nd 01.scf.EuO_primitive_PAW.2.in

&control
    calculation = 'scf',
    restart_mode='from_scratch',
    prefix='00_EuO.Primitive.SOC.PAW.O-nl',
    outdir = '/home/nuttachai/qe-7.0-ReleasePack/qe-7.0_parallel/01_Project_EuO_SOC/00_Primitive/02_PAW_FR_SOC/01.1_Eu-kjpaw_O-nl_SOC',
    pseudo_dir ='/home/nuttachai/qe-7.0-ReleasePack/qe-7.0_parallel/01_Project_EuO_SOC/00_Primitive/02_PAW_FR_SOC',
    verbosity = 'high',
 /
 &system
    ibrav=  0,
    celldm(1) =9.721,
    nat=  2,
    ntyp= 2,
    !nspin= 2,
    noncolin=.true.,
    lspinorb=.true.,
    starting_magnetization(1)=6.9,
    !constrained_magnetization= 'atomic',
    occupations='fixed',
    !tot_magnetization = 7.0,
    !occupations='smearing',
    !smearing='mp',
    degauss=0.001,
    ecutwfc=125.0,
    ecutrho=750.0,
    !nbnd = 96,
    !lda_plus_u=.true.,
    !lda_plus_u_kind = 1,
    !Hubbard_U(1)   = 9.3, Hubbard_J(1,1) = 0.00, Hubbard_J(2,1) =
0.00, Hubbard_J(3,1) = 0.77,
    !Hubbard_U(2)=4.6 , Hubbard_J(1,2)=1.2,
 /
 &electrons
    electron_maxstep = 20000,
    diagonalization = 'david',
    mixing_mode = 'local-TF',
     mixing_beta = 0.05,
    conv_thr =  1.0d-7,
     startingpot = 'file',
    startingwfc = 'file',
 /
CELL_PARAMETERS alat
 0.000  0.500  0.500
 0.500  0.000  0.500
 0.500  0.500  0.000
ATOMIC_SPECIES
Eu 151.964  Eu.rel-pbe-spdfn-kjpaw_psl.1.0.0.UPF,
O  15.999   O.rel-pbe-nl-kjpaw_psl.1.0.0.UPF,
ATOMIC_POSITIONS {crystal}
Eu  0.000 0.000 0.000
O    0.500 0.500 0.500
K_POINTS {automatic}
7 7 7 0 0 0
-------------------------------------------------------------------------------------------------------
3rd  01.scf.EuO_primitive_PAW.3.in

    &control
    calculation = 'scf',
    restart_mode='from_scratch',
    prefix='00_EuO.Primitive.SOC.PAW.O-nl',
    outdir = '/home/nuttachai/qe-7.0-ReleasePack/qe-7.0_parallel/01_Project_EuO_SOC/00_Primitive/02_PAW_FR_SOC/01.1_Eu-kjpaw_O-nl_SOC',
    pseudo_dir ='/home/nuttachai/qe-7.0-ReleasePack/qe-7.0_parallel/01_Project_EuO_SOC/00_Primitive/02_PAW_FR_SOC',
    verbosity = 'high',
 /
 &system
    ibrav=  0,
    celldm(1) =9.721,
    nat=  2,
    ntyp= 2,
    !nspin= 2,
    noncolin=.true.,
    lspinorb=.true.,
    starting_magnetization(1)=6.9,
    !constrained_magnetization= 'atomic',
    !occupations='fixed',
    !tot_magnetization = 7.0,
    occupations='smearing',
    smearing='mp',
    degauss=0.001,
    ecutwfc=125.0,
    ecutrho=750.0,
    !nbnd = 96,
    !lda_plus_u=.true.,
    !lda_plus_u_kind = 1,
    !Hubbard_U(1)   = 9.3, Hubbard_J(1,1) = 0.00, Hubbard_J(2,1) =
0.00, Hubbard_J(3,1) = 0.77,
    !Hubbard_U(2)=4.6 , Hubbard_J(1,2)=1.2,
 /
 &electrons
    electron_maxstep = 20000,
    diagonalization = 'david',
    mixing_mode = 'local-TF',
     mixing_beta = 0.05,
    conv_thr =  1.0d-7,
    ! startingpot = 'file',
    !startingwfc = 'file',
 /
CELL_PARAMETERS alat
 0.000  0.500  0.500
 0.500  0.000  0.500
 0.500  0.500  0.000
ATOMIC_SPECIES
Eu 151.964  Eu.rel-pbe-spdfn-kjpaw_psl.1.0.0.UPF,
O  15.999   O.rel-pbe-nl-kjpaw_psl.1.0.0.UPF,
ATOMIC_POSITIONS {crystal}
Eu  0.000 0.000 0.000
O    0.500 0.500 0.500
K_POINTS {automatic}
7 7 7 0 0 0
-----------------------------------------------------------

Best regards,
Dr. Nuttachai Jutong
Reseaecher
Chiang Mai University,
Thailand