Strange spin-component DOS with spin-orbit coupling

Total energy, geometry optimization, DFT+U, spin....

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JunqingXu
Posts: 1
Joined: Sun Apr 14, 2019 12:14 am

Strange spin-component DOS with spin-orbit coupling

Post by JunqingXu » Sun Apr 14, 2019 2:51 am

Dear developers,
I found that with spin-orbit coupling (nspinor==2) and prtdos==5, the sigma_z projected DOS of non-magnetic system – silicon is non-zero (see figure below). Is it a bug? Can anyone help to figure out this issue?
SpinSpin_DOS.jpg


I put my input file here.

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acell        3*10.263 
rprim
             0.0 0.5 0.5
             0.5 0.0 0.5
             0.5 0.5 0.0
natom        2
typat        1 1
xred         0.00 0.00 0.00
             0.25 0.25 0.25
ntypat       1
znucl       14

ngkpt       16 16 16
kptopt       1
nshiftk      1
shiftk       0.0 0.0 0.0

nspinor      2
ecut        18.0
nband       16
occopt       1
tolwfr       1.0d-16
prtdos       5

DOJO pseudo potential including spin-orbit coupling (NC FR) is used. I run the calculation using one core. I tested other choices of kptopt and ecut and always got the same problem.

Moreover, if I uncomment line 2177 in subroutine cg_getspin in ./src/44_abitools/m_cgtools.f90,

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!write(std_out,*) 'real(spin): ', real(cspin)

the band-resolved spin expectation values can be obtained.
I found that expectation values of sigma_z of two degenerate bands can be the same at some k points rather than negative to each other.

Thanks
Junqing
Junqing Xu
Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA
jxu153@ucsc.edu

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