Dear Evgeniy, I use the following for my graphene dispersion. Please note that the actual coordinates depend on the PSP.
4 0.0 0.0 0.0 150 ! G 0.0000000 -0.577588 0.0 150 ! M -0.3334706 -0.577588 0.0 150 ! K 0.0 0.0 0.0 1 So the matdyn.x code will automatically set 150 points between the first 2 high-symmetry points and so on. Cheers, Vahid On Mar 30, 2021, at 11:58 AM, Evgenii <[email protected]<mailto:[email protected]>> wrote: CAUTION: The Sender of this email is not from within Dalhousie. Dear Vahid, If we use the default values of the q_in_band_form variables, then how do we find intermediate points between the points of high symmetry, as for example on this site https://www.afs.enea.it/buonocor/graphane-with-phonon.html ? Are intermediate points always needed, we noticed that in some examples they are missing. Thanks for the help. Evgeniy Sysoev 30.03.2021, 17:28, "Vahid Askarpour" <[email protected]<mailto:[email protected]>>: The coordinates of the high-symmetry points in matdyn.in should be in cartesian not crystal because you are specifying q_in_band_form=.true. Cheers, Vahid Vahid Askarpour Department of physics and atmospheric science Dalhousie University Halifax, NS CANADA On Mar 30, 2021, at 11:19 AM, Evgenii <[email protected]<mailto:[email protected]>> wrote: CAUTION: The Sender of this email is not from within Dalhousie. Dear Quantum Espresso experts, I am having trouble calculating the phonon bands of graphene. First, I took the cif-file of the already relaxed graphite cell from the Materials Project site https://next-gen.materialsproject.org/ and made graphene cell from it by hand. Then I relaxed the cell obtained with vc-relax and 12x12x1 k-point set. I used the same parameters to perform a scf calculation: &CONTROL calculation='scf' title='graphene' prefix='graphene' verbosity='high' restart_mode='from_scratch' nstep=1000 iprint=1 tstress=.true. tprnfor=.true. disk_io='default' pseudo_dir = '/home/mxm2/Desktop/Graphene', outdir='/home/mxm2/Desktop/Graphene/temp' / &SYSTEM ibrav = 0, celldm(1)=1.889726, nat = 2, ntyp = 1, ecutwfc = 60.0 , ecutrho = 480.0 , / &ELECTRONS electron_maxstep = 1000, conv_thr = 1.0d-12 , mixing_mode = 'plain' , mixing_beta = 0.7d0 , / ATOMIC_SPECIES C 12.011 C.pz-rrkjus.UPF ATOMIC_POSITIONS (crystal) C 0.000000000 0.000000000 0.000861580 C 0.333333000 0.666667000 0.000838420 CELL_PARAMETERS (alat) 2.438515837 -0.000000000 0.000000000 -1.219257919 2.111816662 0.000000000 -0.000000000 -0.000000000 19.995916314 K_POINTS automatic 12 12 1 0 0 0 Then, I run ph.in calculation: &inputph recover=.true. tr2_ph=1.0d-14, prefix='graphene', ldisp=.true. nq1=12, nq2=12, nq3=1, amass(1)=12.011, outdir='/home/mxm2/Desktop/Graphene/temp', fildyn='graphene.dyn', / My q2r: &input fildyn='graphene.dyn', zasr='simple', flfrc='graphene.12x12x1.fc' / Matdyn input: &input asr='simple', amass(1)=12.011, flfrc='graphene.12x12x1.fc', flfrq='graphene.disp.freq' q_in_band_form=.true., / 4 ! number of q-points 0.000 0.000 0.000 10 ! gamma point 0.500 0.000 0.000 10 ! M 0.333 0.333 0.000 10 ! K 0.000 0.000 0.000 1 ! gamma point Plotband: graphene.disp.freq 0 1600 graphene.disp.freq.dat graphene.disp.freq.ps 0 100 0 Why the phonon dispersion does not match the pictures from the papers and for calculations with e.g. 18x18x1 k-point and nq-point sets the output file of graphene.dyn1 look like: Dielectric Tensor: ************************ 166.332153320312 0.000000000000 166.332275390625************************ 0.000000000000 0.000000000000 0.000000000000 1.116060253916 Effective Charges E-U: Z_{alpha}{s,beta} atom # 1 -11117471.575740195811 -0.002632206306 0.000000000000 -0.002632205375-11117471.579664016142 0.000000000000 0.000000000000 0.000000000000 -0.003734609171 Also, what is the best way to set the lattice parameters, via Ibrav or CELL_PARAMETERS? Any help is appreciated. Best regards, Evgeniy Sysoev. <graphene.disp.freq.jpg>_______________________________________________ Quantum ESPRESSO is supported by MaX (www.max-centre.eu<http://www.max-centre.eu/>) users mailing list [email protected]<mailto:[email protected]> https://lists.quantum-espresso.org/mailman/listinfo/users , _______________________________________________ Quantum ESPRESSO is supported by MaX (www.max-centre.eu<https://www.max-centre.eu/>) users mailing list [email protected]<mailto:[email protected]> https://lists.quantum-espresso.org/mailman/listinfo/users _______________________________________________ Quantum ESPRESSO is supported by MaX (www.max-centre.eu<http://www.max-centre.eu>) users mailing list [email protected]<mailto:[email protected]> https://lists.quantum-espresso.org/mailman/listinfo/users
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