[Pw_forum] Parity In presence of Spin-Orbit Coupling
Andrea Dal Corso
dalcorso at sissa.it
Mon Feb 15 10:02:29 CET 2016
On Sun, 2016-02-14 at 01:06 +0330, Riemann Derakhshan wrote:
> Dear QE developer and Users,
>
> I want to calculate the parity of occupied levels in some K-points with QE,
>
> When I turned the Spin-Orbit interaction off in "scf.in" file (graphene as
> sample material) it gave me an expected result, such that the parity
>
> expectation values of bands are equal to +1 and -1 which is normal. But
> by turning the Spin-Orbit interaction on in "scf.in" file and running
>
> "bands.in" with "Bands.x" after "scf.in" it gave the parity expectation
> values equal to +2 and -2, I confused by this result. The "scf.in" and
> "sc.out"
In your system the parity can be deduced from the irreducible
representation G_5+ is even and G_5- is odd. Each representation is
twofold degenerate and the 2, -2 that appear in the character table are
the traces of the the parity operator, not the eigenvalues of the
operator. The 2 that appear close to the eigenvalues instead refer only
to the degeneracy of the states.
HTH,
Andrea
>
> and "bands.out" are attached below.
>
> I want to know is it normal to being parity expectation values equal to +2
> and -2 in presence of Spin-Orbit coupling? if I did make mistake how
>
> can I fix it?
>
> I'll appreciate anyone helping me to solve this problem.
>
> Sincerely Yours
>
> Riemann
>
>
> &control
> ! calculation type self consistent
> calculation = 'scf'
> wf_collect = .true. ,
> prefix = './mol'
> pseudo_dir = './'
> outdir = './'
> wf_collect = .true.
> verbosity = 'high'
> /
> &system
> ibrav = 4
> celldm(1) = 4.65303296132007217931
> celldm(3) = 4.87408610885458976441
> nat = 2
> ntyp = 1
> ecutwfc = 30
> ecutrho = 240
> occupations = 'smearing'
> ! occupations = 'tetrahedra'
> degauss = 0.01
> ! noncolin = .true. ,
> ! lspinorb = .true. ,
> /
> &electrons
> conv_thr = 1.0e-8
> mixing_beta = 0.1
> mixing_mode = 'local-TF'
> electron_maxstep = 100
> /
> &ions
> /
> ATOMIC_SPECIES
> C 12.0107 C.pbe-rrkjus.UPF
> ATOMIC_POSITIONS crystal
> C 0.666666666 0.333333333 0.000000000
> C 0.333333333 0.666666666 0.000000000
> K_POINTS crystal
> 1
> 0.50000000 0.00000000 0.00000000 1
>
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> Bands.out Without Spin-Orbit
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> Program BANDS v.5.1.1 starts on 14Feb2016 at 0:40:22
>
> This program is part of the open-source Quantum ESPRESSO suite
> for quantum simulation of materials; please cite
> "P. Giannozzi et al., J. Phys.:Condens. Matter 21 395502 (2009);
> URL http://www.quantum-espresso.org",
> in publications or presentations arising from this work. More details
> at
> http://www.quantum-espresso.org/quote
>
> Parallel version (MPI), running on 4 processors
> R & G space division: proc/nbgrp/npool/nimage = 4
>
> Info: using nr1, nr2, nr3 values from input
>
> Info: using nr1s, nr2s, nr3s values from input
>
> IMPORTANT: XC functional enforced from input :
> Exchange-correlation = SLA PW PBE PBE ( 1 4 3 4 0 0)
> Any further DFT definition will be discarded
> Please, verify this is what you really want
>
> file C.pbe-rrkjus.UPF: wavefunction(s) 2S 2P renormalized
>
> Parallelization info
> --------------------
> sticks: dense smooth PW G-vecs: dense smooth PW
> Min 90 46 14 6690 2351 432
> Max 91 47 18 6703 2359 436
> Sum 361 187 61 26787 9421 1737
>
>
> negative rho (up, down): 2.652E-05 0.000E+00
> high-symmetry point: 0.5000 0.2887 0.0000 x coordinate 0.0000
>
> Plottable bands written to file mol.band.gnu
> Bands written to file mol.band
>
> **************************************************************************
>
> xk=( 0.50000, 0.28868, 0.00000 )
>
> point group D_2h (mmm)
> there are 8 classes
> the character table:
>
> E C2_z C2_y C2_x i s_xy s_xz s_yz
> A_g 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00
> B_1g 1.00 1.00 -1.00 -1.00 1.00 1.00 -1.00 -1.00
> B_2g 1.00 -1.00 1.00 -1.00 1.00 -1.00 1.00 -1.00
> B_3g 1.00 -1.00 -1.00 1.00 1.00 -1.00 -1.00 1.00
> A_u 1.00 1.00 1.00 1.00 -1.00 -1.00 -1.00 -1.00
> B_1u 1.00 1.00 -1.00 -1.00 -1.00 -1.00 1.00 1.00
> B_2u 1.00 -1.00 1.00 -1.00 -1.00 1.00 -1.00 1.00
> B_3u 1.00 -1.00 -1.00 1.00 -1.00 1.00 1.00 -1.00
>
> the symmetry operations in each class:
> E 1
> C2_z 2
> C2_y 3
> C2_x 4
> i 5
> s_xy 6
> s_xz 7
> s_yz 8
>
> Band symmetry, D_2h (mmm) point group:
>
> e( 1 - 1) = -14.86312 eV 1 --> B_2u
> e( 2 - 2) = -13.83663 eV 1 --> A_g
> e( 3 - 3) = -7.01653 eV 1 --> B_3u
> e( 4 - 4) = -3.02267 eV 1 --> B_3g
> e( 5 - 5) = 1.03648 eV 1 --> B_1u
> e( 6 - 6) = 6.84967 eV 1 --> A_g
> e( 7 - 7) = 10.01521 eV 1 --> B_2u
> e( 8 - 8) = 10.21035 eV 1 --> A_g
>
> **************************************************************************
>
> BANDS : 0.73s CPU 1.04s WALL
>
>
> This run was terminated on: 0:40:23 14Feb2016
>
> =------------------------------------------------------------------------------=
> JOB DONE.
> =------------------------------------------------------------------------------=
>
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> Bands.out With Spin-Orbit
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> Program BANDS v.5.1.1 starts on 14Feb2016 at 0:57:14
>
> This program is part of the open-source Quantum ESPRESSO suite
> for quantum simulation of materials; please cite
> "P. Giannozzi et al., J. Phys.:Condens. Matter 21 395502 (2009);
> URL http://www.quantum-espresso.org",
> in publications or presentations arising from this work. More details
> at
> http://www.quantum-espresso.org/quote
>
> Parallel version (MPI), running on 4 processors
> R & G space division: proc/nbgrp/npool/nimage = 4
>
> Info: using nr1, nr2, nr3 values from input
>
> Info: using nr1s, nr2s, nr3s values from input
>
> IMPORTANT: XC functional enforced from input :
> Exchange-correlation = SLA PW PBE PBE ( 1 4 3 4 0 0)
> Any further DFT definition will be discarded
> Please, verify this is what you really want
>
> file C.pbe-rrkjus.UPF: wavefunction(s) 2S 2P renormalized
>
> Parallelization info
> --------------------
> sticks: dense smooth PW G-vecs: dense smooth PW
> Min 90 46 14 6690 2351 432
> Max 91 47 18 6703 2359 436
> Sum 361 187 61 26787 9421 1737
>
>
> negative rho (up, down): 2.651E-05 0.000E+00
> high-symmetry point: 0.5000 0.2887 0.0000 x coordinate 0.0000
>
> Plottable bands written to file mol.band.gnu
> Bands written to file mol.band
>
> **************************************************************************
>
> xk=( 0.50000, 0.28868, 0.00000 )
>
> double point group D_2h (mmm)
> there are 10 classes and 2 irreducible representations
> the character table:
>
> E -E C2 C2' C2'' i -i s_v s_v' s_v''
> -C2 -C2' -C2'' -s_v -s_v' -s_v'
> G_5+ 2.00 -2.00 0.00 0.00 0.00 2.00 -2.00 0.00 0.00 0.00
> G_5- 2.00 -2.00 0.00 0.00 0.00 -2.00 2.00 0.00 0.00 0.00
>
> the symmetry operations in each class:
> E 1
> C2 -C2 2 -2
> C2' -C2' 3 -3
> C2'' -C2'' 4 -4
> i 5
> s_v -s_v 6 -6
> s_v'-s_v' 7 -7
> s_v''-s_v' 8 -8
> -E -1
> -i -5
>
> Band symmetry, D_2h (mmm) double point group:
>
> e( 1 - 2) = -14.86296 eV 2 --> G_5-
> e( 3 - 4) = -13.83647 eV 2 --> G_5+
> e( 5 - 6) = -7.01634 eV 2 --> G_5-
> e( 7 - 8) = -3.02256 eV 2 --> G_5+
> e( 9 - 10) = 1.03660 eV 2 --> G_5-
> e( 11 - 12) = 6.84981 eV 2 --> G_5+
> e( 13 - 14) = 10.00945 eV 2 --> G_5-
> e( 15 - 16) = 10.20230 eV 2 --> G_5+
>
> **************************************************************************
>
> BANDS : 2.20s CPU 2.59s WALL
>
>
> This run was terminated on: 0:57:17 14Feb2016
>
> =------------------------------------------------------------------------------=
> JOB DONE.
> =------------------------------------------------------------------------------=
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--
Andrea Dal Corso Tel. 0039-040-3787428
SISSA, Via Bonomea 265 Fax. 0039-040-3787249
I-34136 Trieste (Italy) e-mail: dalcorso at sissa.it
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