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<p>Dear Prof. <span>Samir Ranjan Meher </span>,</p>
<p><br>
</p>
<p>The solution is already written in your email:</p>
<p><br>
</p>
<p><font style="font-family: arial narrow, sans-serif, serif, "EmojiFont";" face="arial narrow, sans-serif"> The DOS at the Fermi level is too small:<br>
DOS(E_Fermi) = -0.1639E-79<br>
This means that most likely the system has a gap,<br>
and hence <span style="color: rgb(255, 0, 0);">it should NOT be treated as a metal</span></font><br>
</p>
<p><br>
</p>
<p>Therefore, please remove this from your input file:</p>
<p><font style="font-family: arial narrow, sans-serif, serif, "EmojiFont";" face="arial narrow, sans-serif">> occupations = 'smearing', smearing = 'mv', degauss=0.001</font><br>
</p>
<p><br>
</p>
<p>In any case, if you use linear response theory to compute U for Zn-3d you will obtain a very large value. Check this paper:
<span>K. Yu and E.A. Carter, J. Chem. Phys. 140, 121105 (2014)</span></p>
<p><br>
</p>
<p>HTH</p>
<p><br>
</p>
<p>Iurii<br>
</p>
<p><br>
</p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> users <users-bounces@lists.quantum-espresso.org> on behalf of Samir Ranjan Meher <samirmeher@gmail.com><br>
<b>Sent:</b> Wednesday, November 3, 2021 4:01:43 PM<br>
<b>To:</b> users@lists.quantum-espresso.org<br>
<b>Subject:</b> [QE-users] Error with hp.x while calculating Hubbard U parameter</font>
<div> </div>
</div>
<div>
<div dir="ltr">Hello everyone,
<div><br>
</div>
<div>Greetings.</div>
<div><br>
</div>
<div>I am facing the following error while trying to obtain the "Hubbard-U" parameter for Zn in ZnO through linear response theory using hp.x.</div>
<div><br>
</div>
<div><font face="arial narrow, sans-serif"> WARNING: The Fermi energy shift is too big!<br>
This may happen in two cases:<br>
1. The DOS at the Fermi level is too small:<br>
DOS(E_Fermi) = -0.1639E-79<br>
This means that most likely the system has a gap,<br>
and hence it should NOT be treated as a metal<br>
(otherwise numerical instabilities will appear).<br>
2. Numerical instabilities due to too low cutoff<br>
for hard pseudopotentials.<br>
<br>
Stopping...<br>
STOP 1</font><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div>The scf input file is as follows:</div>
<div>=======================================================<br clear="all">
<div><font face="arial narrow, sans-serif">&control<br>
calculation = 'scf',<br>
prefix='zno',<br>
pseudo_dir = 'D:/Data/samir/qe/pseudo',<br>
outdir='D:/Data/samir/qe/ZnO/hp/tmp'<br>
/<br>
&system <br>
ibrav = 4, nat=4, ntyp= 2, a = 3.2494, c = 5.2038<br>
ecutwfc = 60, ecutrho = 300<br>
occupations = 'smearing', smearing = 'mv', degauss=0.001<br>
lda_plus_U=.TRUE.<br>
lda_plus_U_kind = 0,<br>
U_projection_type = 'ortho-atomic'<br>
Hubbard_U(1)=1.d-10<br>
/<br>
<br>
&ELECTRONS<br>
mixing_mode='plain'<br>
mixing_beta = 0.7,<br>
conv_thr = 1.0d-10,<br>
/<br>
<br>
ATOMIC_SPECIES<br>
Zn 65.39000 Zn.pbesol-dnl-kjpaw_psl.1.0.0.UPF<br>
O 15.99940 O.pbesol-n-kjpaw_psl.1.0.0.UPF<br>
<br>
ATO&control</font></div>
<font face="arial narrow, sans-serif"> calculation = 'scf',<br>
prefix='zno',<br>
pseudo_dir = 'D:/Data/samir/qe/pseudo',<br>
outdir='D:/Data/samir/qe/ZnO/hp/tmp'<br>
/<br>
&system <br>
ibrav = 4, nat=4, ntyp= 2, a = 3.2494, c = 5.2038<br>
ecutwfc = 60, ecutrho = 300<br>
occupations = 'smearing', smearing = 'mv', degauss=0.001<br>
lda_plus_U=.TRUE.<br>
lda_plus_U_kind = 0,<br>
U_projection_type = 'ortho-atomic'<br>
Hubbard_U(1)=1.d-10<br>
/<br>
<br>
&ELECTRONS<br>
mixing_mode='plain'<br>
mixing_beta = 0.7,<br>
conv_thr = 1.0d-10,<br>
/<br>
<br>
ATOMIC_SPECIES<br>
Zn 65.39000 Zn.pbesol-dnl-kjpaw_psl.1.0.0.UPF<br>
O 15.99940 O.pbesol-n-kjpaw_psl.1.0.0.UPF<br>
<br>
ATOMIC_POSITIONS {angstrom}<br>
Zn -0.000016 1.876051 0.000000<br>
Zn 1.624700 0.938040 2.601900<br>
O -0.000016 1.876051 1.988372<br>
O 1.624700 0.938040 4.590272<br>
<br>
K_POINTS {automatic}<br>
8 8 4 0 0 0</font></div>
<div>=================================================================<br>
<div><br>
</div>
<div>Can anybody suggest any solution to this?</div>
<div><br>
</div>
<div>Thank you,</div>
<div>Best wishes</div>
<div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature">
<div dir="ltr">
<div>
<div dir="ltr">Samir Ranjan Meher
<div>Assistant Professor</div>
<div>Department of Physics</div>
<div>School of Advanced Sciences</div>
<div>Vellore Institute of Technology, Vellore</div>
<div>Tamilnadu- 632014</div>
<div>India</div>
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