How to calculate the Hubbard parameter of Ni in NiO using HP.W code

 

The calculation of Hubbard parameters using the HP code is based on DFPT:  Density-Functional Perturbation Theory

We need 3 input files and 2 pseudopotentials

 

NiO.scf1.in

 &control
    calculation='scf'
    restart_mode='from_scratch',
    prefix='NiO'
    pseudo_dir = '/home/algerien/abinitio/q-e-qe-6.8/pseudo/'
    outdir='/home/algerien/abinitio/q-e-qe-6.8/tempdir/'
    verbosity='high'
 /
 &system
    ibrav = 0, 
    celldm(1) = 7.88, 
    nat = 4, 
    ntyp = 3,
    ecutwfc = 50.0,
    ecutrho = 400.0,
    occupations = 'smearing',
    smearing = 'gauss',
    degauss = 0.001,
    nspin = 2,
    starting_magnetization(1) =  0.5,
    starting_magnetization(2) = -0.5,
    lda_plus_u = .true.,
    lda_plus_u_kind = 0,
    U_projection_type = 'ortho-atomic',
    Hubbard_U(1) = 1.d-8
    Hubbard_U(2) = 1.d-8
 /
 &electrons
    conv_thr =  1.d-10
    mixing_beta = 0.7
 /ATOMIC_SPECIES
 Ni1  58.693  ni_lda_v1.4.uspp.F.UPF
 Ni2  58.693  ni_lda_v1.4.uspp.F.UPF
 O    16.000  o_lda_v1.2.uspp.F.UPF
ATOMIC_POSITIONS {alat}
 Ni1  0.0000000   0.0000000   0.0000000
 Ni2  0.5000000   0.5000000   0.0000000
 O    0.5000000   0.0000000   0.0000000
 O    1.0000000   0.5000000   0.0000000
CELL_PARAMETERS
 1.00000000  0.50000000  0.50000000
 0.50000000  1.00000000  0.50000000
 0.50000000  0.50000000  1.00000000
K_POINTS {automatic}
 2 2 2 0 0 0

NiO.scf2.in

 &control
    calculation='scf'
    restart_mode='from_scratch',
    prefix='NiO'
    pseudo_dir = '/home/algerien/abinitio/q-e-qe-6.8/pseudo/'
    outdir='/home/algerien/abinitio/q-e-qe-6.8/tempdir/'
    verbosity='high'
 /
 &system
    ibrav = 0, 
    celldm(1) = 7.88, 
    nat = 4, 
    ntyp = 3,
    ecutwfc = 50.0,
    ecutrho = 400.0,
    nbnd = 29
    occupations = 'fixed'
    nspin = 2,
    tot_magnetization = 0.00
    lda_plus_u = .true.,
    lda_plus_u_kind = 0,
    U_projection_type = 'ortho-atomic',
    Hubbard_U(1) = 1.d-8
    Hubbard_U(2) = 1.d-8
 /
 &electrons
    conv_thr =  1.d-15
    mixing_beta = 0.7
    startingpot = 'file'
    startingwfc = 'file'
 /
ATOMIC_SPECIES
 Ni1  58.693  ni_lda_v1.4.uspp.F.UPF
 Ni2  58.693  ni_lda_v1.4.uspp.F.UPF
 O    16.000  o_lda_v1.2.uspp.F.UPF
ATOMIC_POSITIONS {alat}
 Ni1  0.0000000   0.0000000   0.0000000
 Ni2  0.5000000   0.5000000   0.0000000
 O    0.5000000   0.0000000   0.0000000
 O    1.0000000   0.5000000   0.0000000
CELL_PARAMETERS
 1.00000000  0.50000000  0.50000000
 0.50000000  1.00000000  0.50000000
 0.50000000  0.50000000  1.00000000
K_POINTS {automatic}
 2 2 2 0 0 0

NiO.hp.in

 &inputhp
   prefix = 'NiO',
   outdir = '/home/algerien/abinitio/q-e-qe-6.8/tempdir/',
   nq1 = 2, nq2 = 2, nq3 = 2,
   conv_thr_chi = 1.0d-8,
   iverbosity = 2
 /

 

Pseudopotentials

 ni_lda_v1.4.uspp.F.UPF

 o_lda_v1.2.uspp.F.UPF

It's better to download the file in the pseudo directory $QEROOT/pseudo

You can download the file using the following command

$ cd $QEROOT/pseudo
algerien1970@linux-ml0a:~/abinitio/q-e-qe-6.8/pseudo>
wget https://www.quantum-espresso.org/upf_files/ni_lda_v1.4.uspp.F.UPF --no-check-certificate
wget https://www.quantum-espresso.org/upf_files/o_lda_v1.2.uspp.F.UPF --no-check-certificate

 

Running the first SCF calculation for Nio

algerien1970@linux-ml0a:~/abinitio/QE-tutorials/Hub-Par/NiO> pw.x < NiO.scf1.in |tee NiO.scf1.out

Extracting the number of Kohn-Sham states from the previous run

....../Hub-Par/NiO> grep 'number of Kohn-Sham states' NiO.scf1.out | tail -1 
     number of Kohn-Sham states=           29

The number of bands in Ni.scf2.in must be 29

    nbnd = 29

 

Extracting the value of the total magnetization from the previous run

....../Hub-Par/NiO> grep 'total magnetization' NiO.scf1.out | tail -1 
     total magnetization       =    -0.00 Bohr mag/cell

 Second self-consistent calculation

algerien1970@linux-ml0a:~/abinitio/QE-tutorials/Hub-Par/NiO> pw.x < NiO.scf2.in |tee NiO.scf2.out

 

 Performing the linear-response calculation

algerien1970@linux-ml0a:~/abinitio/QE-tutorials/Hub-Par/NiO> hp.x < NiO.hp.in |tee NiO.hp.out

 

 

The Hubbard parameter values for are in the top of file NiO.Hubbard_parameters.dat

=-------------------------------------------------------------------=

                           Hubbard U parameters:

       site n.  type  label  spin  new_type  new_label  Hubbard U (eV)
         1        1    Ni1     1      1         Ni1        8.4072
         2        2    Ni2    -1      1         Ni1        8.4072

  =-------------------------------------------------------------------=