Which electronic structure method for the study of defects: A commentary

Abstract

Phone: þ216 368 6120, Fax: þ216 368 4679 A historic perspective is provided to the choice of methodologies for point defects in semiconductors. A summary and commentary on the highlights of the CECAM workshop: ''Which electronic structure method for the study of defects?'' is given, attempting to provide a link between the different contributions. To this purpose different themes running through the compilation are identified and rather than discussing individual contributions one by one, the discussion is focused around these themes. The first theme is the problem of correcting for finite size effects. The second theme is the problem of the underestimate of the band gaps and how to correct for it in defect calculations. The third theme is the self-interaction error of local density approximation (LDA) and its repercussions for polaronic defects. The fourth theme is progress in methods beyond LDA that are becoming applicable to point defects, either for ground states or excited state properties.

Electrostatics-based finite-size corrections for first-principles point defect calculations

“…Around the Si + ion, the electrostatic potential is substantially different from the PC potential because of the finite distribution of the electrons. It, however, becomes almost parallel to the PC potential at a distance of ∼ 2 Å from the ion, and the difference converges to a constant of 2πQ 3L 3 . Therefore, after applying the PC correction and alignmentlike correction, i.e.…”

“…Despite the importance, it is difficult to directly and fully study point defects by experiments, and first-principles calculations have emerged as an invaluable tool for modeling and understanding the point defects. [1][2][3] In particular, a rapid progress on the computational speed and electronic structure calculation methods as represented by hybrid functionals, quantum Monte Carlo, and the GW approximation allows us to predict the defect properties semi-quantitatively or even quantitatively in recent years. [4][5][6][7][8][9][10][11][12][13] These calculations support and complement experimental findings.…”

Energetics and metastability of the silicon vacancy in cubic SiC

“…The usual approximations of DFT suffer from the infamous band gap problem. There is nowadays a common agreement that the band gap problem particularly plagues DFT predictions of defect properties in semiconductors and insulators 8 . Point defects in non metallic solids generally produce additional electronic levels inside the band gap region.…”

Charged dopants in semiconductor nanowires under partially periodic boundary conditions

“…A recent review on this subject can be found in Ref. 9 . A widely used prescription to avoid interactions between the jellium and the system has been proposed by Makov and Payne 10 .…”