Virtual crystal description of III-V semiconductor alloys in the tight binding approach

TL;DR

This paper introduces a simplified virtual crystal approximation method for modeling III-V semiconductor alloys using tight-binding parameters, accurately capturing bandgap bowing and aligning well with supercell calculations.

Contribution

It presents a new, compact formulation for strain parameters and linear interpolation of Hamiltonians to effectively model ternary alloys in the virtual crystal approximation.

Findings

Accurately describes bandgap bowing in InGaAsSb alloys

Aligns well with supercell calculation results

Enables atomistic modeling without extensive supercell computations

Abstract

We propose a simple and effective approach to construct the empirical tight-binding parameters of ternary alloys in the virtual crystal approximation. This combines a new, compact formulation of the strain parameters and a linear interpolation of the hamiltonians of binary materials strained to the alloy equilibrium lattice parameter. We show that it is possible to obtain a perfect description of the bandgap bowing of ternary alloys in the InGaAsSb family of materials. Furthermore, this approach is in a good agreement with supercell calculations using the same set of parameters. This scheme opens a way for atomistic modeling of alloy-based opto-electronic devices without extensive supercell calculations.