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Hi everyone,</div>
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I am trying to obtain a converged SCF calculation (using Quantum ESPRESSO, version 7.0) for the medium-entropy oxide (CoCuMgZn)<sub>0.25</sub> O. This material crystalizes in the rocksalt structure. I am using a 64-atom supercell. I have attached my input file
at the end of this message. </div>
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My problem is: after 50 iterations, my calculations show no trend towards convergence (ie. the 'estimated scf accuracies' in the pw.x output file stabilize around 0.5 Ry). I have made the following adjustments in an effort to achieve better convergence:</div>
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<li><span>using degauss values of 0.001, 0.01, 0.02</span></li><li><span>using a 6 x 6 x 6 K-mesh</span></li><li><span>using mixing_beta of 0.05, 0.1, 0.2</span></li><li><span>using ecutwfc of 60, 70, 100 (each with 10x ecutrho)</span></li><li><span>using PBEsol, PBE pseudopotentials</span></li></ul>
<div>My question is: do you think it is possible to achieve a converged SCF calculation using QE? If it is, what might an appropriate value of conv_thr be, and could you suggest other changes to my input file I could try?</div>
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<div>Thank you for your time,</div>
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<div>Connor Wilson</div>
<div>Brock University</div>
<div>Department of Mathematics and Science</div>
<div>1812 Sir Issac Brock Way, St. Catharines, ON, CAN, L2S 3A1</div>
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<div>######################## pw.x input ###########################</div>
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<div>&CONTROL
<div> calculation = 'scf',</div>
<div> prefix = 'MEO',</div>
<div> tstress = .true.,</div>
<div> tprnfor = .true.,</div>
<div> restart_mode = 'from_scratch',</div>
<div> outdir = '/home/cw279/projects/def-crandles/cw279/MEO/222c/alat'</div>
<div> pseudo_dir = '/home/cw279/pseudo',</div>
<div>/</div>
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<div>&SYSTEM</div>
<div> ibrav = 1,</div>
<div> celldm(1) = 15.1,</div>
<div> nat = 64,</div>
<div> ntyp = 5,</div>
<div> ecutwfc = 100,</div>
<div> ecutrho = 1000,</div>
<div> occupations = 'smearing',</div>
<div> smearing = 'mv',</div>
<div> degauss = 0.01,</div>
<div>/</div>
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<div>&ELECTRONS</div>
<div> electron_maxstep = 50,</div>
<div> mixing_beta = 0.1,</div>
<div> conv_thr = 1.0d-6,</div>
<div> mixing_mode = 'local-TF',</div>
<div> mixing_ndim = 10,</div>
<div>/</div>
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<div>ATOMIC_SPECIES</div>
<div> Mg 24.305 Mg.pbe-spnl-kjpaw_psl.1.0.0.UPF</div>
<div> O 15.9994 O.pbe-n-kjpaw_psl.1.0.0.UPF</div>
<div> Zn 65.380 Zn.pbe-dnl-kjpaw_psl.1.0.0.UPF</div>
<div> Ni 58.6934 Ni.pbe-spn-kjpaw_psl.1.0.0.UPF</div>
<div> Co 58.9332 Co.pbe-spn-kjpaw_psl.0.3.1.UPF</div>
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<div>K_POINTS {automatic}</div>
<div> 4 4 4 0 0 0</div>
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<div>ATOMIC_POSITIONS {crystal}</div>
<div>........</div>
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