Dear Vahid, Thank you for your help, changing *q_in_band_form=.true* to *q_in_cryst_coord*=.true resolves the problem as you suggested,
Cheers Roozbeh PDF, Physics, Queen's university On Sat, Jan 23, 2021 at 12:56 AM Roozbeh Anvari <[email protected]> wrote: > > > Dear Quantum Espresso experts, > > I am having a trouble calculating the phonon bands of graphene at > $K$-point, > > I am using NC+LDA and NC+PBE, ecutwfs=60, Ecutrho=400.0, > forc_conv_thr=1.0d-6, > > as you can see in the attached figure, the calculated acoustic and optical > eigenvalues are ok at $\Gamma$ and $M$-points, however the calculated value > deviates from what it should be at $K$-point: > TA and ZA branches are not overlapping at $K$-point, > and a strange bump can be seen when ZO approaches $K$-point, > > I have checked the convergence for K-mesh, Ecutwfs, and Ecutrho, > I have also tried increasing the K and q mesh for scf-calculation, > using tr2_ph = 1E-14 and alpha_mix(niter)= .1 also does not improve the > results, > > > Thank you for your help, > Regards, > Roozbeh > PDF, physics, Queen's university > > > Here is the setup I am using, > > step 1, pw.x > > &CONTROL > .... > calculation='scf' > forc_conv_thr=1.0d-6, > / > > &SYSTEM > ibrav=0, nat = 2, ntyp = 1, > ecutwfc = 60.0 , ecutrho = 400.0, ! 480 > nosym=.true., > occupations='smearing', smearing='cold', degauss=0.02 > la2F = .true., > / > > &ELECTRONS > startingwfc='random' > diagonalization='cg' > conv_thr = 1.0e-12 > mixing_beta = 0.2 > electron_maxstep=200 > > > ATOMIC_SPECIES > C 12.011 C.pz-vbc.UPF > > CELL_PARAMETERS (angstrom) > 2.428479517 -0.000000605 0.000000000 > -1.214240282 2.103124989 0.000000000 > 0.000000000 0.000000000 20.000000000 > > ATOMIC_POSITIONS (crystal) > C -0.0002315717 0.0002344099 0.4996978700 > C 0.6664267343 0.3335704066 0.4996978902 > > K_POINTS automatic > 64 64 1 0 0 0 > > %-------------------- > % step 2 ,pw.x > %-------------------- > > same as above except > la2F = .false., > K_POINTS automatic > 32 32 1 0 0 0 > > %-------------------- > % step 3 , ph.x > %-------------------- > > > &inputph > tr2_ph=1.0d-14, > prefix='ml_gr', > fildvscf='ml_gredv', > amass(1)=12.011, > outdir='./tmp', > fildyn='ml_gr.dyn', > electron_phonon='interpolated', > !el_ph_sigma=0.005, > !el_ph_nsigma=10, > alpha_mix=0.1 > diagonalization='cg', > trans=.true., > ldisp=.true., > nq1=4 , nq2=4, nq3=1 > ! nq1=8 , nq2=8, nq3=1 makes no difference > / > > > %-------------------- > % step 4 , q2r.x > %-------------------- > > &input > zasr='simple', > fildyn='ml_gr.dyn', > flfrc='gr333.fc', > la2F=.true. > / > > > %-------------------- > % step 5 , matdyn.x > %-------------------- > > &input > asr='simple', > amass(1)=12.011, > flfrc='gr333.fc', > flfrq='gr333.freq', > la2F=.true., > dos=.false. > q_in_band_form=.true. > / > 4 > 0 0 0 20 > 0 .5 0 20 > -0.3333333 0.6666666 0. 20 > 0 0 0 1 >
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