Dear users and developers, I posted the below question more than two weeks ago. However, I have not received any response. Any feedback or suggestion is greatly appreciated. Thanks in advance
Zeina ---------- Forwarded message ---------- From: Zeina Al-Dolami <[email protected]> Date: Tue, Apr 28, 2015 at 3:54 PM Subject: flat band structure To: [email protected] Dear Pwscf's developers and users, I have started using quantum espresso recently for my research that focuses on investigating the mechanical and electrical properties of carbon based materials. I ran several examples of wannier90-1.2 to gain more understanding and insight of what I need to consider when running simulations for quantum conductance. However, I have realized that I need to reproduce the band structures of carbon based materials that have been already published then move to using wannier90. I came across this paper http://scitation.aip.org/content/aip/proceeding/aipcp/10.1063/1.3469647 page242. It is basically a linear chain of 5 carbon atoms. Also, Accelrys Software, DMol programme, was used in this paper. I used the below scf and band files to reproduce the same band structure. However, the band structure that was produced contains flat bands only. I went through the pw-forum to find whether there was similar question or not. I found some discussions related to band structure and other suggestions that I have considered but no success, such as http://qe-forge.org/pipermail/pw_forum/2005-December/078012.html . Would you please tell me what I missed in my calculations? It is worth to mention that I have tried to use the same parameters available in this paper in my simulation. Any suggestion and feedback is greatly appreciated. Apologies if my question seems trivial because I am still at the beginning and have no background in this field. Looking forward to hearing from you. Thanks in advance Zeina scf file &CONTROL calculation = 'scf', restart_mode= 'from_scratch', verbosity = 'high' pseudo_dir = '/pseudo', outdir = './', prefix = '5cc', tstress = .f., tprnfor = .t., / &SYSTEM ibrav = 1, ! a = 6.520, ! b = 1.304, ! c = 1.304, celldm(1) = 12.3210, cosbc = 0., cosac = 0., cosab = 0., nat = 5, ntyp = 1, ecutwfc = 30., ecutrho = 240., occupations = 'smearing', smearing = 'cold', degauss = 0.03, nspin = 1, / &ELECTRONS mixing_beta = 0.4 electron_maxstep = 1000, conv_thr = 1.D-10, / ATOMIC_SPECIES C 12.0107 C.pbe-rrkjus.UPF ATOMIC_POSITIONS (angstrom) C 0.183 0.000000000 0.000000000 C 1.489 0.000000000 0.000000000 C 2.791 0.000000000 0.000000000 C 4.093 0.000000000 0.000000000 C 5.399 0.000000000 0.000000000 K_POINTS {automatic} 6 1 1 0 0 0 band file &CONTROL calculation = 'bands', restart_mode= 'from_scratch', verbosity = 'high' pseudo_dir = '/pseudo', outdir = './', prefix = '5cc', tstress = .f., tprnfor = .t., / &SYSTEM ibrav = 1, ! a = 6.520, ! b = 1.304, ! c = 1.304, celldm(1) = 12.3210, cosbc = 0., cosac = 0., cosab = 0., nat = 5, ntyp = 1, ecutwfc = 30., ecutrho = 240., occupations = 'smearing', smearing = 'cold', degauss = 0.03, nspin = 1, / &ELECTRONS mixing_beta = 0.4 electron_maxstep = 1000, conv_thr = 1.D-10, ! diag_full_acc = .true. / ATOMIC_SPECIES C 12.0107 C.pbe-rrkjus.UPF ATOMIC_POSITIONS (angstrom) C 0.183 0.000000000 0.000000000 C 1.489 0.000000000 0.000000000 C 2.791 0.000000000 0.000000000 C 4.093 0.000000000 0.000000000 C 5.399 0.000000000 0.000000000 K_POINTS {crystal} 6 0.00000000 0.00000000 0.00000000 1.00000000 0.16666667 0.00000000 0.00000000 1.00000000 0.33333333 0.00000000 0.00000000 1.00000000 0.50000000 0.00000000 0.00000000 1.00000000 0.66666667 0.00000000 0.00000000 1.00000000 0.83333333 0.00000000 0.00000000 1.00000000 -- Zeina Al-Dolami PhD Candidate Microelectronics and Photonics Graduate Program University of Arkansas Fayetteville, AR 72701 Office: PHYS 244 Email: [email protected] <[email protected]> -- Zeina Al-Dolami PhD Candidate Microelectronics and Photonics Graduate Program University of Arkansas Fayetteville, AR 72701 Office: PHYS 244 Email: [email protected] <[email protected]>
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