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--></style></head><body lang=EN-US link=blue vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><p class=MsoListParagraph>Yes,</p><ol style='margin-top:0in' start=1 type=a><li class=MsoListParagraph style='margin-left:0in;mso-list:l0 level1 lfo1'>I have optimized the bulk cell (with PBE) without so or mbj </li><li class=MsoListParagraph style='margin-left:0in;mso-list:l0 level1 lfo1'>The slab is constructed from the optimized cell. I have generated a supercell 1x1x2 with a vacuum of 40ang and from that a slab of 6ql (quintuple layers) is generated. The space group then changes from 166-R3m to 164-p3m1 keeping the same hexagonal cell. </li><li class=MsoListParagraph style='margin-left:0in;mso-list:l0 level1 lfo1'>After that I have minimized the internal atomic position (relaxation) using msr1 method as available in wine2k code. </li></ol><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Now my question is that, I want to calculate the band structure for the slab with SO coupling. The steps I have mentioned are the correct one or I have to use the DFT-D3 correction. If DFT-D3 is a must one for the topological band structure then what modification/new steps required for the calculation. </p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Regards<o:p></o:p></p><p class=MsoNormal>Burhan Ahmed<o:p></o:p></p><p class=MsoNormal><b>Research Scholar, AUS <o:p></o:p></b></p><p class=MsoNormal><o:p> </o:p></p><div style='mso-element:para-border-div;border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal style='border:none;padding:0in'><b>From: </b><a href="mailto:laurence.marks@gmail.com">Laurence Marks</a><br><b>Sent: </b>Tuesday, June 20, 2023 9:48 AM<br><b>To: </b><a href="mailto:wien@zeus.theochem.tuwien.ac.at">A Mailing list for WIEN2k users</a><br><b>Subject: </b>Re: [Wien] Calculation of surface state using lmbj potential with SO coupling.</p></div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>A very basic question for you -- what is your surface structure? In general, just taking the bulk and cutting it is wrong (too lazy).</p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Before what you said:</p></div><div><p class=MsoNormal>a) Optimize the volume of the bulk cell with your functional of choice, no so or mbj.</p></div><div><p class=MsoNormal>b) Create a representative (e.g. valence neutral) surface slab using the 2D lattice parameters in the surface plane from a).</p></div><div><p class=MsoNormal>c) Optimise the internal positions (-min) as there will be some relaxation. Again no so or mbj. Check that you have, for instance, an insulator. You may have to recreate the surface if you did it wrong. Depending on case you will use run_lapw, runsp_c_lapw or runsp_lapw. Adding DW is optional.</p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Then start with adding mbj & so on. You have to keep your fingers crossed that the structure from c) is a valid representation, since you cannot optimize positions with so & mbj.</p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Depending upon care, 50% probability that you surface structure will be different from nature.</p></div><div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>--<br>Professor Laurence Marks (Laurie)<br>Department of Materials Science and Engineering, Northwestern University<br><a href="http://www.numis.northwestern.edu">www.numis.northwestern.edu</a><br>"Research is to see what everybody else has seen, and to think what nobody else has thought" Albert Szent-Györgyi</p></div></div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>On Tue, Jun 20, 2023, 07:02 Burhan Ahmed <<a href="mailto:burhan.ahmed@aus.ac.in">burhan.ahmed@aus.ac.in</a>> wrote:</p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>Dear experts, I am having a compact cluster with 100gb RAM, 36 cores and 12 TB SATA hard disk with CentOS.</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>I want to calculate the band structure at the surface of topological insulator. Below are the steps I have used for the detailed calculation.</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>After initialization, I run a pbe scf using </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>“run_lapw -p -ec 0.0001 -cc 0.001 -NI”</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>Save the result using </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>“save_lapw <b>pbe</b>”</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>In the next step </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>“init_so_lapw” ( took the default parameters, magnetization is 0 0 1)</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>“Init_nl_vdw “ (kernel type 1)</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>“init_mbj_lapw”</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>“run_lapw -p -so -i 1 -NI”</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>“save_lapw <b>mbj</b>”</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>“init_mbj_lapw”</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>Took the selection 2 for surface calculation, and lmbj for potential </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>And finally I run “run_lapw -p -lmbj -so -ec 0.0001 -cc 0.001 -i 999 -NI”</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>And then I save the result using save_lapw <b>lmbj</b>.</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>I want to know whether these are the correct steps for calculating band structure at the surface or I have to used DFT-D3 for the correction of dispersion which are basically used for the surface calculation. If DFT-D3 must be used for the surface calculation to show Dirac Cone/band inversion nature, then what modification I have to do in my steps to use DFT-D3 so that I can get a clear Band structure with Dirac Cone.</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>Thanks in Advance </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'> </p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>Regards</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'>Burhan Ahmed</p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'><b>Research Scholar, AUS </b></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;margin-left:4.8pt'> </p></div></div></blockquote></div></div></div><p class=MsoNormal style='margin-left:4.8pt'>_______________________________________________<br>Wien mailing list<br><a href="mailto:Wien@zeus.theochem.tuwien.ac.at">Wien@zeus.theochem.tuwien.ac.at</a><br><a href="http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien">http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien</a><br>SEARCH the MAILING-LIST at: <a href="http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html">http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html</a></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>