<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">It is possible to simulate a doped system. However, the only way to do it is using a supercell approach.<div class=""><br class=""></div><div class="">Indeed, doping is usually meant as a “random” distribution of non-interacting (or almost non-interacting)</div><div class="">impurities. As such, you should choose a sufficiently large supercell (for example, try 2x2x2 or 3x3x3 for</div><div class="">a three-dimensional cubic lattice), to prevent the impurity defects in neighbour supercells from interacting.</div><div class=""><br class=""></div><div class="">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 class="">the impurity with an m x m x m supercell, the latter requires, to obtain the same accuracy with</div><div class="">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 class="">1x1x1 bulk unit cell, and study the impurity within a 2x2x2 supercell, for the latter you sample the BZ with</div><div class="">a 3x3x3 k-point grid).</div><div class=""><br class=""></div><div class="">This being said, the larger the supercell, the larger the computational resources (also in terms of RAM)</div><div class="">you need.</div><div class=""><br class=""></div><div class="">If you use, as you say, a “unit cell structure” (I think you mean the same unit cell as the bulk crystal),</div><div class="">you are simulating a possibly interacting distribution of impurities, with concentrations usually much larger</div><div class="">that the experimental ones and with defect levels that possibly exhibit dispersion (“defect bands”).</div><div class=""><br class=""></div><div class="">Giovanni</div><div class=""><br class=""></div><div class="">PS people usually do sign their posts in the forum, together with their affiliation.</div><div class=""><div><br class=""><blockquote type="cite" class=""><div class="">On 8 Jul 2020, at 20:32, Neelam Swarnkar <<a href="mailto:neelamswarnkar35@gmail.com" class="">neelamswarnkar35@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="auto" class="">Dear expert and all<div dir="auto" class=""><br class=""></div><div dir="auto" class="">Doping of an atom is possible in a unit cell structure, because supercell taking a lot RAM for calculation.</div><div dir="auto" class=""><br class=""></div><div dir="auto" class="">If it is possible , than please let me know.</div><div dir="auto" class=""><br class=""></div><div dir="auto" class="">Thanks in advance</div></div>
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<div dir="auto" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div dir="auto" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div style="text-align: start; text-indent: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div style="text-align: start; text-indent: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><span style="color: rgb(0, 0, 0); letter-spacing: normal; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">-- <br class=""><br class="">Giovanni Cantele, PhD</span></div><div style="text-align: start; text-indent: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><span style="color: rgb(0, 0, 0); letter-spacing: normal; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br class="">CNR-SPIN<br class="">c/o Dipartimento di Fisica<br class="">Universita' di Napoli "Federico II"<br class="">Complesso Universitario M. S. Angelo - Ed. 6<br class="">Via Cintia, I-80126, Napoli, Italy</span></div><div style="text-align: start; text-indent: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><span style="color: rgb(0, 0, 0); letter-spacing: normal; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br class=""><a href="mailto:giovanni.cantele@spin.cnr.it" class="">e-mail: giovanni.cantele@spin.cnr.it</a></span></div><div style="text-align: start; text-indent: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><span style="color: rgb(0, 0, 0); letter-spacing: normal; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""> <a href="mailto:gcantele@gmail.com" class="">gcantele@gmail.com</a><br class="">Phone: +39 081 676910<br class="">Skype contact: giocan74<br class="">Web page:<span class="Apple-converted-space"> </span></span><a href="https://sites.google.com/view/giovanni-cantele" class="">https://sites.google.com/view/giovanni-cantele</a></div></div></div></div>
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