Ab initio study of InxGa1−xN – Performance of the alchemical mixing approximation

Abstract

The alchemical mixing approximation which is the ab initio pseudopotential specific implementation of the virtual crystal approximation (VCA), offered in the ABINIT package, has been employed to study the wurtzite (WZ) and zinc blende (ZB) In x Ga 1−x N alloy from first principles. The investigations were focused on structural properties (the equilibrium geometries), elastic properties (elastic constants and their pressure derivatives), and on the band-gap. Owing to the ABINIT functionality of calculating the Hellmann- The idea of tuning the band-gap, although simple in principle, is connected with a variety of practical problems like lattice constants mismatch of parent

The band-gap of Tl-doped gallium nitride alloys

“…Such calculations lead to similar results to those of the virtual crystal approximation, which have been discussed for some nitride systems, e.g. In x Ga 1−x N [27] and AlN 1−x P x [31].…”

Elastic Properties and the Band Gap ofAlNxP1-xSemiconductor Alloy: A Comparative Study of VariousAb InitioApproaches

“…As we have shown before, in these calculations, the SC results should present more trustworthy values as well. In our previous research, we have shown that the local geometry optimization and bond lengths between atoms of different species crucially impact the value of the band gaps [7]. The alchemical mixing does not account for that properly which explains the deviation.…”

“…The finite difference (FD) method of calculating the elastic constants was used in our previous work [7] and gave excellent results. In principle, it is relatively easy and is expected to produce accurate results.…”

“…Two approaches of alloy simulation have been employed: a supercell of 16 and 32 atoms (for zinc-blende and wurtzite structure, resp.) and the alchemical mixing of pseudopotentials [7,8].…”

“…The second one was the alchemical mixing (AM) which was, due to its similarity to the virtual crystal approximation (VCA), called the VCA in our previous papers [21]. A detailed description of the alchemical mixing method can be found in the computational details section of [7].…”