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<p class="gmail-p1" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:"Helvetica Neue";color:rgb(0,0,0)">Dear QE community,</p>
<p class="gmail-p2" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:"Helvetica Neue";color:rgb(0,0,0);min-height:12px"><br></p>
<p class="gmail-p1" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:"Helvetica Neue";color:rgb(0,0,0)">I have difficulty when calculating the band structure for Co3O4. I used the conventional unit cell and optimized the structure. I performed a band structure calculation and I got a small bandgap (about 0.6 eV). This makes sense because Co3O4 is a semi-conductor. Then I performed a band structure calculation with a Hubbard correction and expecting a bigger bandgap. However, the band structure diagram looks very strange. The band was gone, which means the valence band and conduction band are overlapping with each other. I was expecting the band will be bigger because of the Hubbard correction and I was surprised because I got the opposite result. Then I tried to increase the Hubbard value by about 1 eV, the result stays the same: no gaps. and the diagram for both Hubbard correction calculations looks very similar.<span class="gmail-Apple-converted-space"> </span></p>
<p class="gmail-p2" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:"Helvetica Neue";color:rgb(0,0,0);min-height:12px"><br></p>
<p class="gmail-p1" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:"Helvetica Neue";color:rgb(0,0,0)">As I mentioned, I really think the bandgap will be bigger with the Hubbard correction, I believe there is something wrong with my calculation, but I just don’t understand where I got wrong and I am not even sure why the hubbard value is not acting on the metal. How can I explain this phenomenon? Does anyone ever have this similar issue? Any insights about how can I possibly figure this out?<span class="gmail-Apple-converted-space"> </span></p>
<p class="gmail-p2" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:"Helvetica Neue";color:rgb(0,0,0);min-height:12px"><br></p>
<p class="gmail-p1" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:"Helvetica Neue";color:rgb(0,0,0)">Here is the main part of my input file.</p>
<p class="gmail-p2" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:"Helvetica Neue";color:rgb(0,0,0);min-height:12px"><br></p>
<p class="gmail-p1" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:"Helvetica Neue";color:rgb(0,0,0)">Thank you so much!</p>
<p class="gmail-p2" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:"Helvetica Neue";color:rgb(0,0,0);min-height:12px"><br></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">&control</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>calculation <span class="gmail-Apple-converted-space"> </span>= 'scf'</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>restart_mode<span class="gmail-Apple-converted-space"> </span>= 'from_scratch'</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>prefix<span class="gmail-Apple-converted-space"> </span>= ‘$’</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>pseudo_dir<span class="gmail-Apple-converted-space"> </span>= '$$'</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>outdir<span class="gmail-Apple-converted-space"> </span>= '$$$'</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>nstep <span class="gmail-Apple-converted-space"> </span>= 200</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>max_seconds <span class="gmail-Apple-converted-space"> </span>= 324000</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>wf_collect<span class="gmail-Apple-converted-space"> </span>=.FALSE.</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">/</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">&system</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>ibrav=1, celldm(1)=15.1884, nat=56, ntyp=2,</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>ecutwfc=300.0,ecutrho=1200.0,</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>occupations = 'smearing',degauss=0.010d0</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>smearing = 'mp'</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>nspin = 2</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>starting_<span style="background-color:rgb(224,228,9)">mag</span></span><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">netization(1)= 0.1</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>lda_plus_u=.TRUE.</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>Hubbard_U(1)=5.9</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">/</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">&electrons</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>conv_thr=1.0d-6, electron_maxstep=1000,</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>mixing_mode='plain', mixing_beta=0.1,diagonalization='cg'</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">/</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">$ions</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>ion_dynamics='bfgs'</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">/</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">&cell</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>cell_dynamics='bfgs'</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">/</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">ATOMIC_SPECIES</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>Co<span class="gmail-Apple-converted-space"> </span>58.933<span class="gmail-Apple-converted-space"> </span>Co_pbe_v1.2.uspp.F.UPF</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>O <span class="gmail-Apple-converted-space"> </span>15.999<span class="gmail-Apple-converted-space"> </span>O_pbe_v1.2.uspp.F.UPF</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span>ATOMIC_POSITIONS crystal</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">Co<span class="gmail-Apple-converted-space"> </span>0.2499990992<span class="gmail-Apple-converted-space"> </span>0.2499990992<span class="gmail-Apple-converted-space"> </span>0.2499990992</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">***</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">***</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">***</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">O <span class="gmail-Apple-converted-space"> </span>0.1147028366<span class="gmail-Apple-converted-space"> </span>0.3852969334<span class="gmail-Apple-converted-space"> </span>0.1147028366</span></p>
<p class="gmail-p4" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0);min-height:13px"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"></span><br></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">K_POINTS Automatic</span></p>
<p class="gmail-p3" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">4 4 4 0 0 0</span></p>
<p class="gmail-p4" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0);min-height:13px"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"></span><br></p>
<p class="gmail-p5" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Helvetica;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">Sincerely,</span></p>
<p class="gmail-p6" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Helvetica;color:rgb(0,0,0);min-height:13px"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"></span><br></p>
<p class="gmail-p5" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Helvetica;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">Yao</span></p>
<p class="gmail-p6" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Helvetica;color:rgb(0,0,0);min-height:13px"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures"><span class="gmail-Apple-converted-space"> </span></span></p></div>