<div dir="auto">Thanks for replying so quickly</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Jul 9, 2020, 12:10 PM Giovanni Cantele <<a href="mailto:giovanni.cantele@spin.cnr.it">giovanni.cantele@spin.cnr.it</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word;line-break:after-white-space">It is possible to simulate a doped system. However, the only way to do it is using a supercell approach.<div><br></div><div>Indeed, doping is usually meant as a “random” distribution of non-interacting (or almost non-interacting)</div><div>impurities. As such, you should choose a sufficiently large supercell (for example, try 2x2x2 or 3x3x3 for</div><div>a three-dimensional cubic lattice), to prevent the impurity defects in neighbour supercells from interacting.</div><div><br></div><div>Consider that if in the bulk unit cell you sample the Brillouin zone with a n x n x n k-point grid and study</div><div>the impurity with an m x m x m supercell, the latter requires, to obtain the same accuracy with</div><div>respect to the sampling, a n/m x n/m x n/m k-point grid (for example, if you use a 6x6x6 k-point grid in the</div><div>1x1x1 bulk unit cell, and study the impurity within a 2x2x2 supercell, for the latter you sample the BZ with</div><div>a 3x3x3 k-point grid).</div><div><br></div><div>This being said, the larger the supercell, the larger the computational resources (also in terms of RAM)</div><div>you need.</div><div><br></div><div>If you use, as you say, a “unit cell structure” (I think you mean the same unit cell as the bulk crystal),</div><div>you are simulating a possibly interacting distribution of impurities, with concentrations usually much larger</div><div>that the experimental ones and with defect levels that possibly exhibit dispersion (“defect bands”).</div><div><br></div><div>Giovanni</div><div><br></div><div>PS people usually do sign their posts in the forum, together with their affiliation.</div><div><div><br><blockquote type="cite"><div>On 8 Jul 2020, at 20:32, Neelam Swarnkar <<a href="mailto:neelamswarnkar35@gmail.com" target="_blank" rel="noreferrer">neelamswarnkar35@gmail.com</a>> wrote:</div><br><div><div dir="auto">Dear expert and all<div dir="auto"><br></div><div dir="auto">Doping of an atom is possible in a unit cell structure, because supercell taking a lot RAM for calculation.</div><div dir="auto"><br></div><div dir="auto">If it is possible , than please let me know.</div><div dir="auto"><br></div><div dir="auto">Thanks in advance</div></div>
_______________________________________________<br>Quantum ESPRESSO is supported by MaX (<a href="http://www.max-centre.eu/quantum-espresso" target="_blank" rel="noreferrer">www.max-centre.eu/quantum-espresso</a>)<br>users mailing list <a href="mailto:users@lists.quantum-espresso.org" target="_blank" rel="noreferrer">users@lists.quantum-espresso.org</a><br><a href="https://lists.quantum-espresso.org/mailman/listinfo/users" target="_blank" rel="noreferrer">https://lists.quantum-espresso.org/mailman/listinfo/users</a></div></blockquote></div><br><div>
<div dir="auto" style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none;word-wrap:break-word;line-break:after-white-space"><div dir="auto" style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none;word-wrap:break-word;line-break:after-white-space"><div style="text-align:start;text-indent:0px;word-wrap:break-word;line-break:after-white-space"><div style="text-align:start;text-indent:0px;word-wrap:break-word;line-break:after-white-space"><span style="color:rgb(0,0,0);letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px">-- <br><br>Giovanni Cantele, PhD</span></div><div style="text-align:start;text-indent:0px;word-wrap:break-word;line-break:after-white-space"><span style="color:rgb(0,0,0);letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px"><br>CNR-SPIN<br>c/o Dipartimento di Fisica<br>Universita' di Napoli "Federico II"<br>Complesso Universitario M. S. Angelo - Ed. 6<br>Via Cintia, I-80126, Napoli, Italy</span></div><div style="text-align:start;text-indent:0px;word-wrap:break-word;line-break:after-white-space"><span style="color:rgb(0,0,0);letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px"><br><a href="mailto:giovanni.cantele@spin.cnr.it" target="_blank" rel="noreferrer">e-mail: giovanni.cantele@spin.cnr.it</a></span></div><div style="text-align:start;text-indent:0px;word-wrap:break-word;line-break:after-white-space"><span style="color:rgb(0,0,0);letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px">            <a href="mailto:gcantele@gmail.com" target="_blank" rel="noreferrer">gcantele@gmail.com</a><br>Phone: +39 081 676910<br>Skype contact: giocan74<br>Web page:<span> </span></span><a href="https://sites.google.com/view/giovanni-cantele" target="_blank" rel="noreferrer">https://sites.google.com/view/giovanni-cantele</a></div></div></div></div>
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