[QE-users] Spin-orbit coupling (SOC) calculation with ultrasoft pseudopotential (USPP) using QE?
Pacome NGUIMEYA
pacome.nguimeya at gmail.com
Thu Apr 25 14:02:52 CEST 2019
Dear QE users,
I recently calculated the band structure of the Tantalum Arsenide (TaAs)
with SOC using the Projector Augmented Wave (PAW) pseudopotential. I got a
result which is not consistent with what exists in the literature.
Actually, when we include the SOC a small gap should open up at the Fermi
level.
To perform that calculation, I added the following three line in my SCF
input files
*lspinorb = .true.,*
* noncolin = .true.,*
* starting_magnetization = 0.0,*
as did in Quantum Espresso Example 7:
https://github.com/maxhutch/quantum-espresso/blob/master/PW/examples/example07/run_example
and
explained here:
https://www.quantum-espresso.org/Doc/pw_user_guide/node10.html
I thought of changing the pseudopotential (PAW) that I used in order to see
if I get a better result.
So, I thought of using the ultrasoft pseudopotential (USPP) but I found
this link
https://www.researchgate.net/post/If_I_would_like_to_add_spin-orbit_coupling_in_band_structure_calculations_what_changes_should_I_do_in_the_input_file_in_Quantum_ESPRESSO
where
it is said that the option *lspinorb= .TRUE.* works only for PAW potentials
and is not supported for ultrasoft pseudopotentials.
*Are the ultrasoft pseudopotentials not supported for SOC calculation in
QE?*
Below is the input file that I used to perform the SOC calculation
&CONTROL
calculation = 'scf',
prefix = 'TaAs',
restart_mode = 'from_scratch',
pseudo_dir = './',
outdir = './',
etot_conv_thr = 1.0e-5,
wf_collect = .true.
/
&SYSTEM
ibrav = 7,
A = 3.4348002616,
B = 3.4348002616,
C = 11.641,
cosAB = 0,
cosAC = 0,
cosBC = 0,
nat = 8,
ntyp = 2,
ecutwfc = 65,
ecutrho = 400,
occupations = 'smearing',
smearing = 'M-P',
degauss = 0.010,
noncolin = .true.,
lspinorb = .true.,
starting_magnetization(1) = 0.0
/
&ELECTRONS
conv_thr = 1.0e-11,
mixing_mode = 'plain',
mixing_beta = 0.7,
diagonalization = 'cg'
/
ATOMIC_SPECIES
Ta 180.94788 Ta.rel-pbe-spn-kjpaw_psl.0.2.UPF
As 74.9216 As.rel-pbe-n-kjpaw_psl.0.2.UPF
ATOMIC_POSITIONS {crystal}
Ta -0.124991858 0.064689851 0.147167066
Ta 0.875311297 0.310797136 0.394149993
Ta -0.623651114 0.938399569 0.521894272
Ta 0.374704885 0.186136223 0.769306698
As 0.374135075 -0.312099362 0.271944874
As 0.374998589 0.438122101 1.021399771
As -0.125251295 0.561961687 0.646512176
As 0.874744421 -0.188007205 -0.104374866
K_POINTS {automatic}
09 09 09 1 1 1
Thanks
Pacome
*___*
*_____________*Pacome NGUIMEYA
Ph.D. Candidate
Computational Condensed Matter Physics
University of Cape Town (UCT), South Africa
*“Be Yourself; everyone else is already taken.” *
*Oscar Wilde*
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20190425/593e4696/attachment.html>
More information about the users
mailing list