Model GW band structure ofInAsandGaAsin the wurtzite phase

Abstract

We report the first quasiparticle calculations of the newly observed wurtzite polymorph of InAs and GaAs. The calculations are performed in the GW approximation using plane waves and pseudopotentials. For comparison we also report the study of the zinc-blende phase within the same approximations. In the InAs compound the In 4d electrons play a very important role: whether they are frozen in the core or not, leads either to a correct or a wrong band ordering (negative gap) within the Local Density Appproximation (LDA). We have calculated the GW band structure in both cases. In the first approach, we have estimated the correction to the pd repulsion calculated within the LDA and included this effect in the calculation of the GW corrections to the LDA spectrum. In the second case, we circumvent the negative gap problem by first using the screened exchange approximation and then calculating the GW corrections starting from the so obtained eigenvalues and eigenfunctions. This approach leads to a more realistic band-structure and was also used for GaAs. For both InAs and GaAs in the wurtzite phase we predict an increase of the quasiparticle gap with respect to the zinc-blende polytype.

MBE Growth of GaAs Whiskers on Si Nanowires

“…At T g 450 °C, 0.2 and 0.55 µm/h the whiskers are tapered with a base to length aspect ratio of ~20 [7], while the 0.1 µm/h produced a majority of truncated NWs with an almost constant diameter, Figure 1. PL measurements on GaAs whiskers show a photoluminescence peak with a blue shift of about 30 meV, which is larger than expected from quantum confinement in 100 nm diameter zinc-blende GaAs and is in excellent agreement with the theoretical blue shift of wurtzite GaAs [8].…”

Exciting prospects for solids: Exact‐exchange based functionals meet quasiparticle energy calculations

“…Meanwhile a combination of exact-exchange-based DFT functionals (for the structural properties) with quasiparticle energy calculations in the GW approach and the 0 0 G W approximation (for the spectral properties) offer the possibility to develop a better understanding of defect properties untainted by structural artefacts caused by the self-interaction or the band gap underestimation of Kohn-Sham. First 0 0 G W calculations for bulk semiconductors based on hybrid functionals appear to be promising [29][30][31], but more work along these lines is needed in the future.…”

“…With the exception of SIC and sX-LDA hybrid functionals are only slowly being applied to solids. Almost no experience exists in their combination with GW calculations [29][30][31] and we will thus defer a discussion of their properties to the Outlook (Section 7).…”

Internal field induced enhancement and effect of resonance in Raman scattering of InAs nanowires

“…There are quite a few reports in the literature, where the electronic band structure of the WZ phase of InAs has been calculated. 19,20,21,22 In a recent article, 11 it was shown that the band gap related resonant Raman intensity of the TO mode of the InAs NW down-shifts by 110 meV from that of the corresponding bulk material due to the decrease in E 1 gap of the WZ phase of the former. In the inset to Fig.…”