<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=Windows-1252">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 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;}
@font-face
{font-family:"\@Malgun Gothic";}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
span.EmailStyle19
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;
mso-ligatures:none;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style>
</head>
<body lang="EN-US" link="blue" vlink="purple" style="word-wrap:break-word">
<div class="WordSection1">
<p class="MsoNormal">Thank you very much for your kind and helpful reply.<o:p></o:p></p>
<p class="MsoNormal">Indeed, I can’t get the correct stability with PBE+U as claimed.<o:p></o:p></p>
<p class="MsoNormal">Sincerely,<o:p></o:p></p>
<p class="MsoNormal">Ken<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="font-size:12.0pt;color:black">From:
</span></b><span style="font-size:12.0pt;color:black">Wien <wien-bounces@zeus.theochem.tuwien.ac.at> on behalf of Peter Blaha <peter.blaha@tuwien.ac.at><br>
<b>Date: </b>Friday, August 25, 2023 at 11:48 AM<br>
<b>To: </b>wien@zeus.theochem.tuwien.ac.at <wien@zeus.theochem.tuwien.ac.at><br>
<b>Subject: </b>Re: [Wien] Optimized lattice constants using pbe+U<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal">Hard to say without repeating the calculations, but:<br>
<br>
a) I see nothing wrong in your calculation setups/procedure<br>
b) I've seen previously VERY wrong PBE+U results using VASP in other <br>
cases. VASP potentials have been optimized for PBE (and probably for <br>
HSE), and those results are usually ok, but I don't know about PBE+U.<br>
c) At the time when the rutile/anatase stability problem came up, I let <br>
a student try if PBE+U could fix it. It did not do it. But this is long <br>
time ago.<br>
<br>
Maybe repeat one U value with a significantly larger RMT for Ti. Note <br>
that the Hubbard-U is applied only within the spheres in WIEN2k and <br>
since the Ti-3d states are not too localized, there might be an effect.<br>
<br>
Am 24.08.2023 um 17:55 schrieb Park, Ken:<br>
> Dear Wien2k experts,<br>
> <br>
> I have been studying the effect of the Hubbard U on various phases of <br>
> TiO2 using wien2k 23.2. I have observed that some calculated properties <br>
> are different from those reported in literature (mostly with <br>
> pseudopotential) and would like to get your suggestions to see if I have <br>
> made a mistake.<br>
> <br>
> For rutile TiO2 using pbe, my optimized lattice constants are a=4.648 Å <br>
> and c=2.966Å, which are close to the published result of 4.650 and 2.968 <br>
> [1]. However, after I added U= 6eV and ran the optimization, I obtained <br>
> a=4.655 Å and c=3.000Å, in contrast to a=4.687Å and c=3.042Å for U=5 eV <br>
> in [1].<br>
> <br>
> [1] <br>
> <a href="https://pubs.aip.org/aip/jcp/article/135/5/054503/190719/DFT-U-calculations-of-crystal-lattice-electronic">
https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpubs.aip.org%2Faip%2Fjcp%2Farticle%2F135%2F5%2F054503%2F190719%2FDFT-U-calculations-of-crystal-lattice-electronic&data=05%7C01%7CKenneth_Park%40baylor.edu%7Cb8d35a91a0424453225308dba58b2ba2%7C22d2fb35256a459bbcf4dc23d42dc0a4%7C0%7C0%7C638285789393067589%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=95rarsH%2BT0jhSPw59OoUyjyv1LjdEOC2otqdaDMMbIU%3D&reserved=0</a>
<<a href="https://pubs.aip.org/aip/jcp/article/135/5/054503/190719/DFT-U-calculations-of-crystal-lattice-electronic">https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpubs.aip.org%2Faip%2Fjcp%2Farticle%2F135%2F5%2F054503%2F190719%2FDFT-U-calculations-of-crystal-lattice-electronic&data=05%7C01%7CKenneth_Park%40baylor.edu%7Cb8d35a91a0424453225308dba58b2ba2%7C22d2fb35256a459bbcf4dc23d42dc0a4%7C0%7C0%7C638285789393067589%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=95rarsH%2BT0jhSPw59OoUyjyv1LjdEOC2otqdaDMMbIU%3D&reserved=0</a>><br>
> <br>
> So I performed a systemic study using U=3, 5, 8, 10 eV as in [1] and <br>
> obtained the following:<br>
> <br>
> U=3 a=4.650 c=2.985 vs U=3 <br>
> a=4.671 c=3.012 [1]<br>
> <br>
> U=5 a=4.649 c=2.995 vs <br>
> U=5 a=4.687 c=3.042 [1]<br>
> <br>
> U=8 a=4.652 c=3.011 vs <br>
> U=8 a=4.709 c=3.081 [1]<br>
> <br>
> U=10 a=4.655 c=3.021 vs <br>
> U=10 a=4.725 c=3.108 [1]<br>
> <br>
> The lattice constant a is nearly constant or expanded very little <br>
> despite the increasing U whereas the constant c shows a similar increase <br>
> albeit by smaller amount. In rutile, c is the direction of the Ti-Ti <br>
> short chain.<br>
> <br>
> I have checked the band gaps and they are comparable with the reported <br>
> results.<br>
> <br>
> U=3 2.24 eV vs U=3 2.15 eV [1]<br>
> <br>
> U=5 2.42 eV vs U=5 2.3 eV [1]<br>
> <br>
> U=8 2.72 eV vs U=8 2.7 eV [1]<br>
> <br>
> U=10 2.98 eV vs U=10 2.92 eV [1]<br>
> <br>
> For your information, I have copied the input files case.inorb and <br>
> case.indm and the top portion of the structure file.<br>
> <br>
> 1 1 0 nmod, natorb, ipr<br>
> <br>
> PRATT 1.0 BROYD/PRATT, mixing<br>
> <br>
> 1 1 2 iatom nlorb, lorb<br>
> <br>
> 1 nsic 0..AMF, 1..SIC, 2..HFM<br>
> <br>
> 0.44 0.00 U J (Ry) Note: you can also use U_eff = U-J and J=0<br>
> <br>
> -12. Emin cutoff energy<br>
> <br>
> 1 number of atoms for which density matrix is <br>
> calculated<br>
> <br>
> 1 1 2 index of 1st atom, number of L's, L1<br>
> <br>
> 0 0 r-index, (l,s)index<br>
> <br>
> TiO2<br>
> <br>
> P 2<br>
> <br>
> RELA<br>
> <br>
> 8.788126 8.788126 5.669865 90.000000 90.000000 90.000000<br>
> <br>
> ATOM -1: X=0.00000000 Y=0.00000000 Z=0.00000000<br>
> <br>
> MULT= 2 ISPLIT= 8<br>
> <br>
> -1: X=0.50000000 Y=0.50000000 Z=0.50000000<br>
> <br>
> Ti NPT= 781 R0=0.00005000 RMT= 1.7800 Z: 22.00000<br>
> <br>
> 0.7071068 0.7071068 0.0000000<br>
> <br>
> -0.7071068 0.7071068 0.0000000<br>
> <br>
> 0.0000000 0.0000000 1.0000000<br>
> <br>
> ATOM -2: X=0.30509790 Y=0.30509790 Z=0.00000000<br>
> <br>
> MULT= 4 ISPLIT= 8<br>
> <br>
> -2: X=0.69490210 Y=0.69490210 Z=0.00000000<br>
> <br>
> -2: X=0.19490210 Y=0.80509790 Z=0.50000000<br>
> <br>
> -2: X=0.80509790 Y=0.19490210 Z=0.50000000<br>
> <br>
> O NPT= 781 R0=0.00010000 RMT= 1.6100 Z: 8.00000<br>
> <br>
> 0.0000000-0.7071068 0.7071068<br>
> <br>
> 0.0000000 0.7071068 0.7071068<br>
> <br>
> -1.0000000 0.0000000 0.0000000<br>
> <br>
> 16 NUMBER OF SYMMETRY OPERATIONS<br>
> <br>
> I optimized the structure with ‘runsp_lapw -p -orb -min -ec 0.00001 -cc <br>
> 0.0001 -fc 1’ (or smaller fc) using rkmax 9 (or 10 to check for <br>
> convergence) and default values such as k-mesh and gmax. I also used two <br>
> different ways to check the optimization: one varying volume and varying <br>
> c/a, and the second varying a and c. Both methods yielded the same or <br>
> consistent results.<br>
> <br>
> I am not sure if I have errored using pbe+U and if so, where, but I <br>
> would very much appreciate your advice.<br>
> <br>
> Sincerely,<br>
> <br>
> Ken Park<br>
> <br>
> <br>
> _______________________________________________<br>
> Wien mailing list<br>
> Wien@zeus.theochem.tuwien.ac.at<br>
> <a href="http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien">https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fzeus.theochem.tuwien.ac.at%2Fmailman%2Flistinfo%2Fwien&data=05%7C01%7CKenneth_Park%40baylor.edu%7Cb8d35a91a0424453225308dba58b2ba2%7C22d2fb35256a459bbcf4dc23d42dc0a4%7C0%7C0%7C638285789393067589%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=XyYSxMN%2BZKqL128pP3YZlsoDLPQoKV32AaWR3pFodbk%3D&reserved=0</a><br>
> SEARCH the MAILING-LIST at: <a href="http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html">
https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.mail-archive.com%2Fwien%40zeus.theochem.tuwien.ac.at%2Findex.html&data=05%7C01%7CKenneth_Park%40baylor.edu%7Cb8d35a91a0424453225308dba58b2ba2%7C22d2fb35256a459bbcf4dc23d42dc0a4%7C0%7C0%7C638285789393067589%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=rBendnyULMW1EDkvHc7j2sYBk4SCmzQtVqbE0AjdUFs%3D&reserved=0</a><br>
<br>
-- <br>
--------------------------------------------------------------------------<br>
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna<br>
Phone: +43-1-58801-165300<br>
Email: peter.blaha@tuwien.ac.at WIEN2k: <a href="http://www.wien2k.at/">https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.wien2k.at%2F&data=05%7C01%7CKenneth_Park%40baylor.edu%7Cb8d35a91a0424453225308dba58b2ba2%7C22d2fb35256a459bbcf4dc23d42dc0a4%7C0%7C0%7C638285789393067589%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=5UxwIV%2F1BHxbForOz5gMFvF7LeNFPETqxEwRYGIdeL0%3D&reserved=0</a><br>
WWW: <a href="http://www.imc.tuwien.ac.at/">https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.imc.tuwien.ac.at%2F&data=05%7C01%7CKenneth_Park%40baylor.edu%7Cb8d35a91a0424453225308dba58b2ba2%7C22d2fb35256a459bbcf4dc23d42dc0a4%7C0%7C0%7C638285789393067589%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=qaH45uEin0UWieM%2BwR1qi%2BxNBcwtlPGqBXyUk6ZInh0%3D&reserved=0</a><br>
-------------------------------------------------------------------------<br>
_______________________________________________<br>
Wien mailing list<br>
Wien@zeus.theochem.tuwien.ac.at<br>
<a href="http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien">https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fzeus.theochem.tuwien.ac.at%2Fmailman%2Flistinfo%2Fwien&data=05%7C01%7CKenneth_Park%40baylor.edu%7Cb8d35a91a0424453225308dba58b2ba2%7C22d2fb35256a459bbcf4dc23d42dc0a4%7C0%7C0%7C638285789393067589%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=XyYSxMN%2BZKqL128pP3YZlsoDLPQoKV32AaWR3pFodbk%3D&reserved=0</a><br>
SEARCH the MAILING-LIST at: <a href="http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html">
https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.mail-archive.com%2Fwien%40zeus.theochem.tuwien.ac.at%2Findex.html&data=05%7C01%7CKenneth_Park%40baylor.edu%7Cb8d35a91a0424453225308dba58b2ba2%7C22d2fb35256a459bbcf4dc23d42dc0a4%7C0%7C0%7C638285789393067589%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=rBendnyULMW1EDkvHc7j2sYBk4SCmzQtVqbE0AjdUFs%3D&reserved=0</a><o:p></o:p></p>
</div>
</div>
</body>
</html>