BEFORE trying vc-relax (what is the structure corresponding to the band structure you give in input?), try calculation=relax and calculate band structure.
Why do you need nbnd=200? For SURE ecutrho is WRONG. For norm-conserving pseudo potentials (as yours), ecutrho = 4 * ecutwfc (a smaller value will definitely produce WRONG results, to what extent is maybe unpredictable), otherwise ecutrho is usually 6 to 12 times ecutwfc. Are you sure about your pseudos? Finally: how do you set the “zero energy”? Giovanni > On 6 Mar 2017, at 12:55, Anindya Bose <[email protected]> wrote: > > Dear Sir, > I have used this code but I didn't get the direct band gap structure of > monolayer WSe2. > &CONTROL > calculation='vc-relax', > outdir='monolayer WSe2', > prefix='calc', > pseudo_dir='/home/anindya/Desktop/pseudopotential', > verbosity='high', > disk_io='high', > wf_collect=.true., > nstep = 50, > etot_conv_thr=1d-02, > forc_conv_thr=1d-02, > / > > &SYSTEM > ibrav=4, > celldm(1)=6.2020811408d0, celldm(3)=4.3566118221d0, > nat=3, > ntyp=2, > ecutwfc=40.0d0, > ecutrho =130.0d0, > nbnd=200, > vdw_corr='Grimme-D2', > force_symmorphic=.true., > input_dft='PBE', > occupations='fixed', > / > > &ELECTRONS > diagonalization='david', > conv_thr=1d-08, > mixing_mode='plain', > mixing_beta=0.700d0, > / > > &ions > ion_dynamics ='bfgs', > / > > &cell > cell_dynamics ='bfgs', > cell_factor=15, > / > > ATOMIC_SPECIES > Se 78.960000d0 Se_ONCV_PBE-1.0_r.oncvpsp.upf > W 183.840000d0 W_ONCV_PBE-1.1_r.oncvpsp.upf > > ATOMIC_POSITIONS {alat} > W 0.5000000000d0 0.2886751346d0 2.1782995738d0 > Se 0.5000000000d0 -0.2886751346d0 1.6692977456d0 > Se 0.5000000000d0 -0.2886751346d0 2.6873014019d0 > > K_POINTS {automatic} > 10 10 1 0 0 0 > > I have enclosed my output band structure with this mail.Can you please help > me in this regard.How can I get the correct band diagram of monolayer > WSe2(direct bandgap). I have used all the codes for spin calculation and I > got the spin orbit coupling but didn't find perfect band diagram.I will be > waiting for your response. > > On Wed, Mar 1, 2017 at 9:04 PM, Giovanni Cantele > <[email protected] <mailto:[email protected]>> wrote: > I never use ism, maybe you can read relevant papers in the literature. > However, if your purpose is just to simulate an isolated monolayer, just add > to the lattice vector orthogonal to the monolayer > plane (a3, in your case) vacuum space, so if the current length is, just to > make an example, 5 A, try to use 15 A. This is the so called supercell > approach, discussed several times in the forum. > > Giovanni > >> On 1 Mar 2017, at 16:17, Anindya Bose <[email protected] >> <mailto:[email protected]>> wrote: >> >> Actually I have used esm_bc to add vacuum in the structure.How can I add >> vacuum in this monolayer WSE2 structure using quantum espresso.Which code >> should be used. >> >> On Wednesday, March 1, 2017, Giovanni Cantele <[email protected] >> <mailto:[email protected]>> wrote: >> It is not clear how and to what extend your band structure differs from shat >> you expect. >> However, one issue I can see is that if you want to study MONOLAYER WSe2, >> you should be aware of the fact that the vacuum space, separating the >> periodic replicas >> along your z direction should be large enough to prevent them from >> interacting (otherwise, you are considering a periodic crystal also along >> that direction). Currently, as far as I can see such vacuum is < 5A, >> definitely too small to simulate a monolayer. Additionally, you also include >> vdw_corr, usually introduced >> to better describe inter-layer interaction, whereas you are claiming that >> you want to study a system composed by a single layer. >> Also, I think that you don’t need to use the variable esm_bc just to >> calculate the properties of a monolayer. >> >> Giovanni >> >> >> >> >> > On 1 Mar 2017, at 14:01, Anindya Bose <[email protected] <>> wrote: >> > >> > Dear Sir, >> > >> > &CONTROL >> > calculation='nscf', >> > outdir='monolayer WSe2', >> > prefix='calc', >> > pseudo_dir='/home/anindya/Desktop/pseudopotentials', >> > verbosity='low', >> > disk_io='high', >> > wf_collect=.true., >> > etot_conv_thr=1d-02, >> > forc_conv_thr=1d-02, >> > / >> > >> > &SYSTEM >> > noncolin=.true., >> > lspinorb=.true., >> > ibrav=0, >> > celldm(1)=6.2020811408d0, celldm(3)=4.3566118221d0, >> > nat=3, >> > ntyp=2, >> > ecutwfc=40.0d0, >> > nbnd=200, >> > vdw_corr='Grimme-D2', >> > starting_magnetization=0.05, >> > force_symmorphic=.true., >> > input_dft='PBE', >> > esm_bc='bc1', >> > no_t_rev=.false., >> > / >> > >> > &ELECTRONS >> > diagonalization='david', >> > conv_thr=1d-08, >> > mixing_mode='plain', >> > mixing_beta=0.700d0, >> > / >> > >> > &ions >> > ion_dynamics ='bfgs', >> > / >> > >> > &cell >> > cell_dynamics ='bfgs', >> > cell_factor=15, >> > / >> > >> > ATOMIC_SPECIES >> > Se 78.960000d0 Se_ONCV_PBE-1.0_nr.oncvpsp.upf >> > W 183.840000d0 W_ONCV_PBE-1.1_nr.oncvpsp.upf >> > >> > CELL_PARAMETERS (alat= 6.20208114) >> > 1.008112278 0.000000000 0.000000000 >> > -0.504056139 0.873050842 0.000000000 >> > 0.000000000 0.000000000 2.445357065 >> > >> > ATOMIC_POSITIONS {alat} >> > W 0.504056139 0.291016947 1.222674975 >> > Se 0.504056139 -0.291016947 0.699051439 >> > Se 0.504056139 -0.291016947 1.746298512 >> > >> > >> > K_POINTS {crystal_b} >> > 4 >> > # Gamma-K-M-Gamma >> > 0 0 0 20 !G >> > 0.33 0.33 0 20 !K >> > 0.5 0 0 20 !M >> > 0 0 0 20 !G >> > >> > I am not getting the WSe2 monolayer band structure, can you please help me >> > in this regard. >> > _______________________________________________ >> > Pw_forum mailing list >> > [email protected] <> >> > http://pwscf.org/mailman/listinfo/pw_forum >> > <http://pwscf.org/mailman/listinfo/pw_forum> >> >> -- >> >> Giovanni Cantele, PhD >> CNR-SPIN >> c/o Dipartimento di Fisica >> Universita' di Napoli "Federico II" >> Complesso Universitario M. S. Angelo - Ed. 6 >> Via Cintia, I-80126, Napoli, Italy >> e-mail: [email protected] <> >> Phone: +39 081 676910 >> Skype contact: giocan74 >> >> ResearcherID: http://www.researcherid.com/rid/A-1951-2009 >> <http://www.researcherid.com/rid/A-1951-2009> >> Web page: http://people.na.infn.it/~cantele >> <http://people.na.infn.it/~cantele> >> >> >> >> _______________________________________________ >> Pw_forum mailing list >> [email protected] <> >> http://pwscf.org/mailman/listinfo/pw_forum >> <http://pwscf.org/mailman/listinfo/pw_forum>_______________________________________________ >> Pw_forum mailing list >> [email protected] <mailto:[email protected]> >> http://pwscf.org/mailman/listinfo/pw_forum >> <http://pwscf.org/mailman/listinfo/pw_forum> > -- > > Giovanni Cantele, PhD > CNR-SPIN > c/o Dipartimento di Fisica > Universita' di Napoli "Federico II" > Complesso Universitario M. S. Angelo - Ed. 6 > Via Cintia, I-80126, Napoli, Italy > e-mail: [email protected] <mailto:[email protected]> > Phone: +39 081 676910 > Skype contact: giocan74 > > ResearcherID: http://www.researcherid.com/rid/A-1951-2009 > <http://www.researcherid.com/rid/A-1951-2009> > Web page: http://people.na.infn.it/~cantele > <http://people.na.infn.it/~cantele> > > > _______________________________________________ > Pw_forum mailing list > [email protected] <mailto:[email protected]> > http://pwscf.org/mailman/listinfo/pw_forum > <http://pwscf.org/mailman/listinfo/pw_forum> > > <WSe2_spin_monolayer.png>_______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum -- Giovanni Cantele, PhD CNR-SPIN c/o Dipartimento di Fisica Universita' di Napoli "Federico II" Complesso Universitario M. S. Angelo - Ed. 6 Via Cintia, I-80126, Napoli, Italy e-mail: [email protected] Phone: +39 081 676910 Skype contact: giocan74 ResearcherID: http://www.researcherid.com/rid/A-1951-2009 Web page: http://people.na.infn.it/~cantele
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