<html><head></head><body><div class="ydp51424671yahoo-style-wrap" style="font-family:lucida console, sans-serif;font-size:13px;"><div><div dir="ltr" data-setdir="false"><font size="1">Dear Abdul Muhaymen,</font></div><div dir="ltr" data-setdir="false"><font size="1"><br></font></div><div dir="ltr" data-setdir="false"><font size="1">You say that your results are fine, except the band gap ! How did you correct it in pure ZnS, before Co-doping ? <br></font></div><div dir="ltr" data-setdir="false"><font size="1">The most commun way in DFT is hybrid functionals (like HSE 06), which obviously are very demanding in computational cost. So the DFT+U (+V) could be a nice alternative. Here I think you might need on-site U not only for Co, but also for Zn (and as you said may be S). Since ZnS is a band insulator and covalent compound, the inter-site V could play an important role.</font></div><div dir="ltr" data-setdir="false"><font size="1"><br></font></div><div dir="ltr" data-setdir="false"><font size="1">In principle U and V <span><font style="background-color: inherit;" size="1">parameters are neither transferable nor universal</font></span>, but in your case ( calculated U from 8 atoms unit cell to use in 64 atoms supercell), I<span><font style="background-color: inherit;" size="1"> guess </font></span>it should be OK !<br></font></div><div dir="ltr" data-setdir="false"><font size="1"><br></font></div><div dir="ltr" data-setdir="false"><font size="1">Best regards<br></font></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false"> <br></div><div><br></div><div class="ydp51424671signature"><div style="text-align:left;font-family:sans-serif;font-size:13px;" dir="ltr" data-setdir="false"><font style="font-family:lucida console, sans-serif;" size="2">=============================</font><font size="2">========<br style="font-family:lucida console, sans-serif;"></font><div><font size="2"><font style="font-family:lucida console, sans-serif;">Dr. Abdesalem HOUARI</font></font></div><font size="2"><font style="font-family:lucida console, sans-serif;">-------------------------------------------------------------------------------------------</font><br style="font-family:lucida console, sans-serif;"><font style="font-family:lucida console, sans-serif;">Department of physics, Theoretical Physics Laboratory</font><br style="font-family:lucida console, sans-serif;"><font style="font-family:lucida console, sans-serif;"><a>University of Bejaia</a>-06000. Algeria</font><font style="font-family:lucida console, sans-serif;">.</font><br style="font-family:lucida console, sans-serif;"><font style="font-family:lucida console, sans-serif;">E-mail: <span style="text-decoration-line: underline; text-decoration-style: solid; text-decoration-color: currentcolor;"><a>abdeslam.houari@univ-bejaia.dz</a></span> & <a>habdslam@yahoo.fr</a></font><br style="font-family:lucida console, sans-serif;"><font style="font-family:lucida console, sans-serif;"><span style="text-decoration-line: underline; text-decoration-style: solid; text-decoration-color: currentcolor; background-color: rgb(0, 0, 255); font-style: italic;"></span></font><a style="font-family:lucida console, sans-serif;" href="https://sites.google.com/site/houariabdeslam/homepage" rel="nofollow" target="_blank">https://sites.google.com/site/houariabdeslam/homepage</a><br style="font-family:lucida console, sans-serif;"><font style="font-family:lucida console, sans-serif;">===================================</font><span style="font-family:lucida console, sans-serif;"></span></font><br></div></div></div>
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On Tuesday, 21 May 2024 at 04:17:30 am GMT+1, Abdul Muhaymin via users <users@lists.quantum-espresso.org> wrote:
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<div><div dir="ltr">Hello all,<br></div><div dir="ltr"><br></div><div dir="ltr">I am investigating single TM dopant in wide band gap semiconductors such <br></div><div dir="ltr">as Co in ZnS. I am using a 64 atoms supercell where I replaced one of <br></div><div dir="ltr">the Zn atom with a Co atom. I tested several convergence with respect to <br></div><div dir="ltr">the supercell size. My results seem fine except the band gap. Now I want <br></div><div dir="ltr">to apply the U correction to that Co-3d (and maybe to S-2p). For this, <br></div><div dir="ltr">is it possible to use the unit cell (8 atoms) and run hp.x to get the U <br></div><div dir="ltr">values? Or do I have to run hp.x with the large supercell (2*2*2 unit <br></div><div dir="ltr">cell=64 atoms)?<br></div><div dir="ltr"><br></div><div dir="ltr">Also, at the beginning of our studies, during the structural relaxation <br></div><div dir="ltr">phase, we first found our lattice parameter for the host semiconductor <br></div><div dir="ltr">from multiple scf calculations and subsequently running an eos analysis <br></div><div dir="ltr">(ev.x). Then we ran relax calculation but not vc-relax. We keep this <br></div><div dir="ltr">lattice parameter constant and when introducing new dopants, we only <br></div><div dir="ltr">vary the atomic positions (calculation='relax'). In this case, when <br></div><div dir="ltr">running hp.x, could we replace the vc-relax calculation with relax <br></div><div dir="ltr">calculation to self-consistently get the U values?<br></div><div dir="ltr"><br></div><div dir="ltr">Thanks,<br></div><div dir="ltr">Abdul Muhaymin<br></div><div dir="ltr">Graduate (MS) student, Materials Science and Nanotechnology<br></div><div dir="ltr">Bilkent University, Ankara.<br></div><div dir="ltr"><br></div><div dir="ltr">_______________________________________________<br></div><div dir="ltr">The Quantum ESPRESSO community stands by the Ukrainian<br></div><div dir="ltr">people and expresses its concerns about the devastating<br></div><div dir="ltr">effects that the Russian military offensive has on their<br></div><div dir="ltr">country and on the free and peaceful scientific, cultural,<br></div><div dir="ltr">and economic cooperation amongst peoples<br></div><div dir="ltr">_______________________________________________<br></div><div dir="ltr">Quantum ESPRESSO is supported by MaX (www.max-centre.eu)<br></div><div dir="ltr">users mailing list <a href="mailto:users@lists.quantum-espresso.org" rel="nofollow" target="_blank">users@lists.quantum-espresso.org</a><br></div><div dir="ltr"><a href="https://lists.quantum-espresso.org/mailman/listinfo/users" rel="nofollow" target="_blank">https://lists.quantum-espresso.org/mailman/listinfo/users</a><br></div></div>
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