Effects of microscopic strain distribution on Ga(1-x)In(x)As quantum wires grown by strain-induced lateral ordering

TL;DR

This paper theoretically investigates how microscopic strain distribution affects the electronic and optical properties of Ga(1-x)In(x)As quantum wires grown by strain-induced lateral ordering, highlighting the role of local atomic arrangements.

Contribution

It introduces a comprehensive atomistic model combining EBOM and VFF to analyze strain effects and optical anisotropy in SILO quantum wires, revealing shear-strain engineering potential.

Findings

Local atomic arrangements significantly alter strain distribution.

Optical anisotropy can be reversed by shear strain changes.

Good agreement with experimental data on band gap and anisotropy.

Abstract

Band Structures and optical matrix elements of quantum wires(QWR's) made of short-period superlattices(SPS) with strain-induced lateral ordering(SILO) are investigated theoretically via an effective bond-orbital model(EBOM) combined with a valence-force field(VFF) model. Valence-band anistropy, band mixing, and effects due to local strain distribution at the atomistic level are all taken into account. In particular, Ga(1-x)In(x)As QWR's grown by SILO process are considered. A VFF model is used to find the equilibrium atomic positions in the SILO QWR structure by minimizing the lattice energy. The strain tensor at each atomic(In or GA) site is then obtained and included in the calculations of electronic states and optical peroperties. It is found that different local arrangement of atoms leads to very different strain distribution, which in term alters the optical properties. In particular, we found that the optical anisotropy can be reversed due to the change in shear strain caused by the inter-change of atomic positions. Good agreement with the existing experimental data on band gap and optical anisotropy can be obtained when a 2D alloy structure with lateral composition modulation in the InAs/GaAs interface planes of the SPS is used. Our studies revealed the possibility of "shear-strain engineering" in SILO QWR light-emitting devices to achieve desired optical anisotropy.