<html><body><div style="font-family: arial,helvetica,sans-serif; font-size: 12pt; color: #000000"><div>Hi. My two cents:<br></div><div><br></div><div>do you have some experimental references to compare your band structure and band gap with? <br></div><div><br></div><div>In my opinion, if you really want to use yambo, maybe better than a scissor operator (how big it should be?) try to calculate the GW correction to your eigenvalues.<br></div><div><br></div><div>If so, I think you should read carefully the exact procedure to prepare a yambo run.<br> Look at the tutorial.<br></div><div>http://www.yambo-code.org/tutorials/index.php</div><div><br></div><div>HTH<br></div><div>Federico<br></div><div><br></div><div><span name="x"></span><table class="mceItemTable" xmlns="urn:zimbraAccount"><tbody><tr><td><img alt="Université Paris-Sud" src="https://zimbra.u-psud.fr/public/z_logo_signature.png" style="border: 0pt none;width:120px;height:107px;background:url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAHgAAABrBAMAAABOCFvUAAAAHlBMVEX8//t9goSEv0OutbhxdngNXILX6sOr1H/Y3uBema/9PDtXAAAF7UlEQVR4Xu3Wv4+byhYH8GOcC6RjBIVLi4JpseBJbkdL4TJStFK2G1FAiyigxfJeya+7UhQpf+77nhkwttc31/FK771iT2wGD/PhDPODDd0fH+GLd+BlegaqfowGIMPHN4ctjv72kGVDhi8dsvRwxBm+2xN123gKDZwTiWWR4rATAy1Xm6IIclWsllERbLJCFNuiUCcbz0ETVgHj15T2QT4Qbch/WgQoU1I4pVO0s5UnHD4xRvs8tZjEfvUWe/Ec6xNe5QPwcodfGzwvMqM32wmfntk5w3rG+wDYD/2Q8MzDZiF2tFepxUWxe9vrmGa8CIEp4twpuvsacudX1902SvYc3YTVcuULwXATWIxzomV4C0tNc+Tbw9NyRbkC2Ecpfh/xzGLwj4cp8/F4htcXy0dFAdwCGOcD7iICQYunvYjS3OBCKAa+xQ2dx2FL/kB+hgMvt+PxOBxRIOg40JF8PkN8JmoNfiQ+D1Q+jv8y85w8hP2vZmlLeiieB/PQ3QzsCE1nNsVUgeL8+o9v5F2N90YgMuYLu/WWXBFuwYonIt9cN/hPpC4vdQ4bFSEUzyxjxRUKpwp4X8Aqg/94fiFqL/RGFAUa8O7F0WBUKAHIWET4ZfHy+fknuUbrCYembyu0EzgCF0h6iCKDlwpVU/x4fv5Obj9rxtAixHeF8xHzMge2PxDjQ7Omet4eAPa4VMFeDBOGsjiYsf+MeLE6ucSfomERpdcY34vU0IPResbodi7IV8GEFxZTFIWXqaFT1skJHzAuGF98R+zn0WDwXkXhcNL/nnQbyxFnWRQFJuurMPiQCaXIYD9XRXjZcWhe5dpgXhWKFoIjShlvcBIYDB2h8mK6EN+ojBuDmaW0FyYCxihDshhaiN2MfasHN17bzFk2oLQ4tHhLFo+Lna41UicG2zoRHhEbwXgfrc4wvWLwzoL1C3nn2K5DLBNgX6nhDC8u8WfbbzljrC/bLgXGPVYXmYmuU/9FvcW2QWrvsQPmQRoYm1cn5u0W7macj4MinhjTfpyqRYGIdrewZmX7FtmC8uLAeKnUjNXwFn8xKsvsYK8sXgieOJ65lHjeMkR6aX1YZP69OI7xrwcwZmiMd+PhHfhlBAd+Pwb2FfDJDO72n/E3a/2I39MT5jd2VKx+jedeLxRnO2EBLtTwSzwP116wohFHOB6ECH6JX37OfzHoCqMz4d/gr1gy2yPRjIdrzNviNv5yVYfdd41pE92JFwLgCu9R3IUpEmp7hRd34yV0+iimQyHCRzG0itKHMUY8eHDAEL7azdjO/f2YgFVwer37QtBvZfbNkrRqI1a38ct1hw5YrpsogNseN2LnZ9uNEukt/NZSzttfDLRXKAuMOiKkW/g77A3Mrf3cqFe2A90ZGWJLBJ2FKM1/zR+Lj/iIZfZg0H89PkK/w7bxbe3oubyKfgJe4iU3sXcHdhrSXqzrto913zZe27Sd1ybcIRnjAnApieq2i227xosltd2Eqa3XZRXX67ZLnK7uei9p3aTVssIFYFk2ZK+jXSedTnpdf8I9rWuStG6pd7RTlV7j1I2jE5JVQk6V4BZ8PekpKanHB230iKuOkpp6d8R9b7DHuO+AZd8QXz/Dvc3srb0EbsQJcOMCV2vO3JMmlC5Z3LprxhopXDIRx00ZNxbHIG4sGccxcBmvCQMQj5nRjtPG0rRh7HbkVuRSRbqtiZNoFzeu8ZtQSaTRwl4n266q0Ab4Mlq6Pzx9hWv6Pwj3gUve2yfA5N7YMW6n3+CSrgO4obdR951pL/njtDyruk08mXja0TXvDNQDA8SJu8a/uHGl5J3SNl1fcX5Zu7LUWO0kayq1JxvGJbU1VoU22O1awpotqwRNG+BOdxVjb03u2uMakhWVhMk3GMhN6sZgwj5oPd1Wcmyqyav1JcZeLfU5lr3N7MlWO/B9N2G79iBPWHtri5vS4jWRwQ7fVBJazHjaGNS2ZojitnESYFfGugbiehxwN1S4CTkyucauthvD5QL35i7ZDWAqaKwgLjRf56b/4/gPHroRZdvxtdsAAAAASUVORK5CYII=" data-mce-src="https://zimbra.u-psud.fr/public/z_logo_signature.png" data-mce-style="border: 0pt none; width: 120px; height: 107px; background: url(data:image/png;"></td><td valign="top"><div><span style="font-size: 10pt" data-mce-style="font-size: 10pt;"><b>Federico IORI</b></span></div><div><span style="font-size: 10pt" data-mce-style="font-size: 10pt;">Marie Curie Fellow<br>Laboratoire de Physique des Solides<br>Bâtiment 510 - Rue André Rivière<br>91400 Orsay</span></div></td></tr></tbody></table><div><br></div><span name="x"></span><br></div><hr id="zwchr"><div style="color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;" data-mce-style="color: #000; font-weight: normal; font-style: normal; text-decoration: none; font-family: Helvetica,Arial,sans-serif; font-size: 12pt;"><b>De: </b>"Christoph Wolf(신소재공학과)" <chwolf@postech.ac.kr><br><b>Para: </b>"pw forum" <pw_forum@pwscf.org><br><b>Enviados: </b>Miércoles, 7 de Septiembre 2016 8:50:59<br><b>Asunto: </b>[Pw_forum] Convergence or band-gap problem in orthorhombic CsPbBr3<br><div><br></div><style><!--
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:"Malgun Gothic";
panose-1:2 11 5 3 2 0 0 2 0 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:"\@Malgun Gothic";
panose-1:2 11 5 3 2 0 0 2 0 4;}
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:#954F72;
text-decoration:underline;}
p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph
{mso-style-priority:34;
margin-top:0cm;
margin-right:0cm;
margin-bottom:0cm;
margin-left:36.0pt;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri",sans-serif;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
@list l0
{mso-list-id:249781954;
mso-list-type:hybrid;
mso-list-template-ids:-1067781870 67698705 67698713 67698715 67698703 67698713 67698715 67698703 67698713 67698715;}
@list l0:level1
{mso-level-text:"%1\)";
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level2
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level3
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
@list l0:level4
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level5
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level6
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
@list l0:level7
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level8
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;}
@list l0:level9
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
ol
{margin-bottom:0cm;}
ul
{margin-bottom:0cm;}
--></style><div class="WordSection1"><p class="MsoNormal">Dear all!</p><p class="MsoNormal"> </p><p class="MsoNormal">I am currently trying to simulate the electronic properties of CsPbBr3 in its low-temperature phase (orthorhombic; a=8.244, b=11.735, c=8.198 angstrom, according to Stoumpos; Cryst. Growth Des. 2013); My principle plan is to follow Radi et al. (arXiv:1405.1706v2), who have done this using Wien2k, muffin-tin potentials. Eventually I want to continue processing this with YAMBO (doesn’t take US PP), so I am using normcons PBE (from the standard repository).</p><p class="MsoNormal"> </p><p class="MsoNormal">However, the band-gap obtained is really tiny (without SOC, SOC is known to further reduce the gap in this material); I have done the following:</p><p class="MsoNormal"> </p><p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1" data-mce-style="text-indent: -18.0pt; mso-list: l0 level1 lfo1;"><span style="mso-list:Ignore" data-mce-style="mso-list: Ignore;">1)<span style="font:7.0pt "Times New Roman"" data-mce-style="font: 7.0pt 'Times New Roman';"> </span></span>Used the CIF file provided by stoumpos et al to create my unit cell and double checked with xcrysden –pwi if it turns out properly</p><p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1" data-mce-style="text-indent: -18.0pt; mso-list: l0 level1 lfo1;"><span style="mso-list:Ignore" data-mce-style="mso-list: Ignore;">2)<span style="font:7.0pt "Times New Roman"" data-mce-style="font: 7.0pt 'Times New Roman';"> </span></span>Tested convergence wrt. Total energy leading to a good compromise with ecutwfc =60.0 (tested between 30 and 180 Ry) and a unshifted automatic 4x3x4 k-grid (tested up to 16x16x16).</p><p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1" data-mce-style="text-indent: -18.0pt; mso-list: l0 level1 lfo1;"><span style="mso-list:Ignore" data-mce-style="mso-list: Ignore;">3)<span style="font:7.0pt "Times New Roman"" data-mce-style="font: 7.0pt 'Times New Roman';"> </span></span>Run Relax (gamma only) – scf – bands along G-X-S-R-G</p><p class="MsoNormal"> </p><p class="MsoNormal">The resulting band structure is in the pdf. The band gap at R is so tiny (0.x eV) that I am not sure if applying scissors in yambo is justified. I also tried smaller degauss and fixed occupations to not much success. If someone can spot an obvious error in my input or has any hint how I can improve my results I would be very grateful! Thank you in advance for your time and help!</p><p class="MsoNormal"> </p><p class="MsoNormal">Yours,</p><p class="MsoNormal">Chris</p><p class="MsoNormal"> </p><p class="MsoNormal">PS: I have also tried a VC-relax which clearly favors a shrinking cell (the cubic phase of CsPbBr3 for example is a=5.605 A, so the Pnma cell is probably far away from 0K – how to deal with this problem when trying to do a 300K phase…?)</p><p class="MsoNormal"> </p><p class="MsoNormal">My scf input:</p><p class="MsoNormal"> </p><p class="MsoNormal">&control</p><p class="MsoNormal"> calculation = 'scf'</p><p class="MsoNormal"> restart_mode='from_scratch',</p><p class="MsoNormal"> prefix='cspbbr3',</p><p class="MsoNormal"> pseudo_dir = '. /pseudo/',</p><p class="MsoNormal"> outdir='./'</p><p class="MsoNormal"> wf_collect=.true.</p><p class="MsoNormal"> verbosity='high'</p><p class="MsoNormal">/</p><p class="MsoNormal">&SYSTEM</p><p class="MsoNormal"> ibrav = 8</p><p class="MsoNormal"> celldm(1)= 15.5789</p><p class="MsoNormal"> celldm(2)= 1.4235</p><p class="MsoNormal"> celldm(3)= 0.9944</p><p class="MsoNormal"> nat = 5</p><p class="MsoNormal"> ntyp = 3</p><p class="MsoNormal"> ecutwfc =60.0</p><p class="MsoNormal"> occupations='smearing'</p><p class="MsoNormal"> smearing='mp'</p><p class="MsoNormal"> degauss=0.002</p><p class="MsoNormal"> force_symmorphic=.true.</p><p class="MsoNormal"> vdw_corr='grimme-d2'</p><p class="MsoNormal">/</p><p class="MsoNormal">&electrons</p><p class="MsoNormal">diago_full_acc=.true.,</p><p class="MsoNormal">conv_thr=1.0d-8</p><p class="MsoNormal">diagonalization='david'</p><p class="MsoNormal">electron_maxstep=300</p><p class="MsoNormal">/</p><p class="MsoNormal">ATOMIC_SPECIES</p><p class="MsoNormal"> Pb 207.20000 Pb.pbe-d-hgh.UPF</p><p class="MsoNormal"> Cs 132.90500 Cs.pbe-sp-hgh.UPF</p><p class="MsoNormal"> Br 79.90400 Br.pbe-hgh.UPF</p><p class="MsoNormal">ATOMIC_POSITIONS (crystal)</p><p class="MsoNormal">Pb 0.500000000 0.495569542 0.500000000</p><p class="MsoNormal">Cs 0.000000000 -0.000054173 0.000000000</p><p class="MsoNormal">Br 0.000000000 0.496389920 0.500000000</p><p class="MsoNormal">Br 0.500000000 0.002099521 0.500000000</p><p class="MsoNormal">Br 0.500000000 0.496980388 0.000000000</p><p class="MsoNormal">K_POINTS {automatic}</p><p class="MsoNormal">4 3 4 0 0 0</p><p class="MsoNormal"> </p><p class="MsoNormal"> </p><p class="MsoNormal">My bands input</p><p class="MsoNormal">nbnd=200 ! include plenty of empty bands for yambo</p><p class="MsoNormal"> </p><p class="MsoNormal">And</p><p class="MsoNormal"> </p><p class="MsoNormal">K_POINTS {crystal_b}</p><p class="MsoNormal">5</p><p class="MsoNormal"> 0.0000000000 0.0000000000 0.0000000000 10 !G</p><p class="MsoNormal"> 0.5000000000 0.0000000000 0.0000000000 10 !X</p><p class="MsoNormal"> 0.5000000000 0.5000000000 0.0000000000 10 !S</p><p class="MsoNormal"> 0.5000000000 0.5000000000 0.5000000000 10 !R</p><p class="MsoNormal"> 0.0000000000 0.0000000000 0.0000000000 10 !G</p><p class="MsoNormal"> </p><p class="MsoNormal"> </p><p class="MsoNormal"> </p><div style="mso-element:para-border-div;border:none;border-bottom:solid windowtext 1.0pt;padding:0cm 0cm 1.0pt 0cm" data-mce-style="mso-element: para-border-div; border: none; border-bottom: solid windowtext 1.0pt; padding: 0cm 0cm 1.0pt 0cm;"><p class="MsoNormal" style="border:none;padding:0cm" data-mce-style="border: none; padding: 0cm;">Christoph Wolf</p><p class="MsoNormal" style="border:none;padding:0cm" data-mce-style="border: none; padding: 0cm;"> </p></div><p class="MsoNormal"><span style="font-family:"Arial",sans-serif" data-mce-style="font-family: 'Arial',sans-serif;">Department of Materials Science and Engineering, POSTECH</span></p><p class="MsoNormal"><span style="font-family:"Arial",sans-serif" data-mce-style="font-family: 'Arial',sans-serif;">RIST #3, 3152, San 31 Hyoja-dong, Nam-gu, Pohang, Kyungbuk, 790-784, Republic of Korea</span></p><p class="MsoNormal"> </p><p class="MsoNormal"> </p><p class="MsoNormal"> </p><p class="MsoNormal"> </p></div><p><br></p><br> <img src="http://home.postech.ac.kr/wp-content/themes/postech/images/mail_logo_postech30.png" src="http://home.postech.ac.kr/wp-content/themes/postech/images/mail_logo_postech30.png"><div style="display:none;" data-mce-style="display: none;">30POSTECH</div><br>_______________________________________________<br>Pw_forum mailing list<br>Pw_forum@pwscf.org<br>http://pwscf.org/mailman/listinfo/pw_forum</div><div><br></div></div></body></html>