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<div class="moz-forward-container">Could anyone tell me how to write
the right codes and execute the right commands to get the matrix
elelments from the valence bands to the conduction bands at the
Brilloun Zone in Quantum espresso?</div>
<div class="moz-forward-container">Thank you very much!</div>
<div class="moz-forward-container"><br>
</div>
<div class="moz-forward-container">Best regards,</div>
<div class="moz-forward-container">Jingjing<br>
</div>
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<td>[Extern] [QE-users] how to extract the matrix elements
from the valence bands to conduction bandsat the Brillouin
zone center?</td>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">Date: </th>
<td>Thu, 9 Nov 2023 23:43:53 +0100</td>
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<td>Yu, Jingjing <a class="moz-txt-link-rfc2396E" href="mailto:jy95vowa@studserv.uni-leipzig.de"><jy95vowa@studserv.uni-leipzig.de></a></td>
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<td>Quantum ESPRESSO users Forum
<a class="moz-txt-link-rfc2396E" href="mailto:users@lists.quantum-espresso.org"><users@lists.quantum-espresso.org></a></td>
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<td><a class="moz-txt-link-abbreviated" href="mailto:users@lists.quantum-espresso.org">users@lists.quantum-espresso.org</a></td>
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<p>Hello everyone,</p>
<p>I am wondering how to extract the matrix elements from the
valence bands to the conduction bands at the Brillouin zone
center, Gamma point in Quantum espresso.</p>
<p>I tried to calculate the matrix elements of Si and I got the
result in the p_avg.dat. But it looks weird, because the the
corresponding matrix elements along x, y ,z directions (for
example, <span
style="font-size: 12pt; line-height: 107%; color: black;">three
values </span><!--[if gte mso 9]><xml>
<o:OfficeDocumentSettings>
<o:AllowPNG/>
</o:OfficeDocumentSettings>
</xml><![endif]--><span style="color:black;mso-themecolor:text1">|<i
style="mso-bidi-font-style:normal">M</i><sub>11</sub>|<sup>2</sup></span><span
style="font-size:14.0pt;line-height:107%;font-family:"Times New Roman",serif;
color:black;mso-themecolor:text1;background:white"></span><span
style="font-size: 12pt; line-height: 107%; color: black;">along
x.y,z directions)</span> are totally different shown below.</p>
<p><b>&p_mat nbnd= 6, nks= 29 /<br>
0.000000 0.000000 0.000000 4<br>
1<br>
0.00022045 0.02823071 0.03700090 0.13449672<br>
0.00458980 0.00203767 0.00400515 0.00964742<br>
2<br>
0.00327610 0.02056865 0.04947954 0.00093171<br>
0.00019941 0.07363126 0.09566180 0.03136617<br>
3<br>
0.00146403 0.07631971 0.06399219 0.00701410<br>
0.00016914 0.00944635 0.02901511 0.16348040</b><br>
</p>
<p>Because Si has face-centered cubic crystal structure and the
matrix elements located at the same positions along x, y, z
directions should be same, right?</p>
<p>My general calculation procedures are shown below: </p>
<p><b>1. run scf.in</b></p>
<p>&control<br>
calculation = 'scf'<br>
restart_mode='from_scratch'<br>
prefix = 'si'<br>
outdir = './outdir'<br>
pseudo_dir = '/home/yyb/qe-7.0/pseudo'<br>
/<br>
&system<br>
ibrav=2, celldm(1) =10.410909236, <br>
nat=2, ntyp=1,<br>
ecutwfc=40<br>
ecutrho=320<br>
nbnd=6<br>
occupations='smearing', smearing='gaussian',degauss=0.005<br>
!nosym = .true.<br>
!noinv = .true.<br>
!occupations = 'fixed'<br>
!input_dft = 'gaupbe'<br>
!nqx1 = 4, nqx2 = 4, nqx3 = 4,<br>
!x_gamma_extrapolation = .false.<br>
! exxdiv_treatment = 'none'<br>
/<br>
&electrons<br>
conv_thr=1e-10<br>
/<br>
ATOMIC_SPECIES<br>
Si 28.0855 Si_ONCV_PBE-1.0.upf<br>
<br>
ATOMIC_POSITIONS (alat)<br>
Si 0.00 0.00 0.00<br>
Si 0.25 0.25 0.25<br>
K_POINTS (automatic)<br>
8 8 8 0 0 0 <br>
</p>
<p><b>2.run bands.x</b></p>
<p>&bands<br>
outdir='./outdir/'<br>
prefix='si'<br>
filband='si.bands.dat'<br>
lp=.true.<br>
filp = 'p_avg.dat'<br>
/<br>
</p>
I don't know how to get the right result and could anyone who has
the experience give me some help or suggestions? </div>
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