No one replies :-( I also write my affiliation now at the end of email. Still no reply
Asad Mahmood, Research Student, Department of Physics, QAU, Islamabad, Pakistan On Fri, Sep 28, 2018 at 4:26 PM Asad Mahmood <[email protected]> wrote: > Here is the input file: > > &control > calculation = 'scf' > restart_mode='from_scratch', > pseudo_dir = './../../../Pseudo', > prefix='arsenene', > verbosity = 'high' > / > &system > ibrav = 4, > nat= 2, ntyp= 1, > ibrav= 4, > celldm(1) =7.8, > celldm(3) =6.103648, > > ecutwfc =30.0, > occupations='smearing', > smearing='gauss', degauss=0.02, > lspinorb=.true > noncolin=.true > nbnd = 20 > / > &electrons > !diagonalization='david' > electron_maxstep = 300 > !mixing_mode = 'plain' > mixing_beta = 0.7 > conv_thr = 1.0d-10 > / > ATOMIC_SPECIES > As 74.9216 As.rel-pbe-n-rrkjus_psl.0.2.UPF > ATOMIC_POSITIONS crystal > As 0.333333333 0.666666666 0.524859275 > As 0.666666666 0.333333333 0.475140725 > K_POINTS crystal > 1 > 0.5 0.0 0.0 1 > > > Note that in the above highlighted portion I am using one of the TRIM > points, i.e. M1. Where other TRIM points are M2, M3 and G with coordinates > 0.0 0.5 0.0, -0.5 0.0 0.0 and 0.0 0.0 0.0 respectively. > After SCF (pw.x) calculation, I run the bands,x calculation. The relevant > portion of the output is : > > ************************************************************************** > > xk=( -0.50000, 0.28868, 0.00000 ) > > double point group C_2h (2/m) > there are 8 classes and 4 irreducible representations > the character table: > > E -E C2 -C2 i -i s_h -s_h > > G_3+ 1.00 -1.00 0.00 0.00 1.00 -1.00 0.00 0.00 > G_4+ 1.00 -1.00 0.00 0.00 1.00 -1.00 0.00 0.00 > G_3- 1.00 -1.00 0.00 0.00 -1.00 1.00 0.00 0.00 > G_4- 1.00 -1.00 0.00 0.00 -1.00 1.00 0.00 0.00 > > imaginary part > > E -E C2 -C2 i -i s_h -s_h > > G_3+ 0.00 0.00 1.00 -1.00 0.00 0.00 1.00 -1.00 > G_4+ 0.00 0.00 -1.00 1.00 0.00 0.00 -1.00 1.00 > G_3- 0.00 0.00 1.00 -1.00 0.00 0.00 -1.00 1.00 > G_4- 0.00 0.00 -1.00 1.00 0.00 0.00 1.00 -1.00 > > the symmetry operations in each class and the name of the first > element: > > E 1 > > -E -1 > > C2 2 > > -C2 -2 > > i 3 > > -i -3 > > s_h 4 > > -s_h -4 > > > Band symmetry, C_2h (2/m) double point group: > > e( 1 - 2) = -14.19192 eV 2 --> G_3- > e( 1 - 2) = -14.19192 eV 2 --> G_4- > e( 3 - 4) = -12.67503 eV 2 --> G_3+ > e( 3 - 4) = -12.67503 eV 2 --> G_4+ > e( 5 - 6) = -6.29105 eV 2 --> G_3+ > e( 5 - 6) = -6.29105 eV 2 --> G_4+ > e( 7 - 8) = -5.79866 eV 2 --> G_3- > e( 7 - 8) = -5.79866 eV 2 --> G_4- > e( 9 - 10) = -4.65984 eV 2 --> G_3- > e( 9 - 10) = -4.65984 eV 2 --> G_4- > e( 11 - 12) = -2.39948 eV 2 --> G_3+ > e( 11 - 12) = -2.39948 eV 2 --> G_4+ > e( 13 - 14) = -0.22470 eV 2 --> G_3- > e( 13 - 14) = -0.22470 eV 2 --> G_4- > e( 15 - 16) = 0.10174 eV 2 --> G_3+ > e( 15 - 16) = 0.10174 eV 2 --> G_4+ > e( 17 - 18) = 2.74250 eV 2 --> G_3+ > e( 17 - 18) = 2.74250 eV 2 --> G_4+ > e( 19 - 20) = 3.59948 eV 2 --> G_3- > e( 19 - 20) = 3.59948 eV 2 --> G_4- > > Is highlighted K point in the output file okay?? since I used 0.5 0 0 but > it is xk=( -0.50000, 0.28868, 0.00000 ). > Moreover, I get the same result for M2 and M3 (which should not happen > because then Z2 = 0 which contradicts the dedfinitions of TI) > > Please help. > > > On Thu, Sep 27, 2018 at 4:19 PM Asad Mahmood <[email protected]> > wrote: > >> Hi everyone, >> >> I am working with 2D materials, applying biaxial strain. At some strain >> value, the electronic structure exhibits the band diagram similar to that >> of a Topological Insulator (as I could observe band inversion from partial >> DOS too). The material I am working with has inversion symmetry which >> implies that I can find parity eigen values at different bands(then I can >> find Z2 Topological Invariant using parity eigen values). >> My question is: >> >> How can we obtain parities (or directly Z2 values, if possible) using >> Quantum Espresso for a given band diagram? >> >> Regards, >> Asad Mahmood, >> Physics Department, >> Q.A.U, Islamabad, >> Pakistan >> >
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