Thanks for replying so quickly On Thu, Jul 9, 2020, 12:10 PM Giovanni Cantele <[email protected]> wrote:
> It is possible to simulate a doped system. However, the only way to do it > is using a supercell approach. > > Indeed, doping is usually meant as a “random” distribution of > non-interacting (or almost non-interacting) > impurities. As such, you should choose a sufficiently large supercell (for > example, try 2x2x2 or 3x3x3 for > a three-dimensional cubic lattice), to prevent the impurity defects in > neighbour supercells from interacting. > > 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 > the impurity with an m x m x m supercell, the latter requires, to obtain > the same accuracy with > 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 > 1x1x1 bulk unit cell, and study the impurity within a 2x2x2 supercell, for > the latter you sample the BZ with > a 3x3x3 k-point grid). > > This being said, the larger the supercell, the larger the computational > resources (also in terms of RAM) > you need. > > If you use, as you say, a “unit cell structure” (I think you mean the same > unit cell as the bulk crystal), > you are simulating a possibly interacting distribution of impurities, with > concentrations usually much larger > that the experimental ones and with defect levels that possibly exhibit > dispersion (“defect bands”). > > Giovanni > > PS people usually do sign their posts in the forum, together with their > affiliation. > > On 8 Jul 2020, at 20:32, Neelam Swarnkar <[email protected]> > wrote: > > Dear expert and all > > Doping of an atom is possible in a unit cell structure, because supercell > taking a lot RAM for calculation. > > If it is possible , than please let me know. > > Thanks in advance > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users > > > -- > > Giovanni Cantele, PhD > > CNR-SPIN > c/o Dipartimento di Fisica > Universita' di Napoli "Federico II" > Complesso Universitario M. S. Angelo - Ed. 6 > Via Cintia, I-80126, Napoli, Italy > > e-mail: [email protected] <[email protected]> > [email protected] > Phone: +39 081 676910 > Skype contact: giocan74 > Web page: https://sites.google.com/view/giovanni-cantele > > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users
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