Structural and Electronic Properties of a Wide-gap Semiconductor Alloy: Zn_xMg_{1-x}S_ySe_{1-y}

TL;DR

This study investigates the structural and electronic properties of the Zn_xMg_{1-x}S_ySe_{1-y} alloy, revealing how short-range order influences phase stability and energy gap, using computational methods including cluster expansion and Monte Carlo simulations.

Contribution

It combines computational alchemy, cluster expansion, and Monte Carlo simulations to determine the phase diagram and short-range order effects in the alloy.

Findings

Homogeneous phase exhibits significant short-range order among first neighbors.

Energy gap is highly sensitive to short-range order.

Phase diagram indicates stability regions for the alloy.

Abstract

The structural properties of the $Zn_xMg_{1-xS_ySe_{1-y}}$ solid solutions are determined by a combination of the computational alchemy and the cluster expansion methods with Monte Carlo simulations. We determine the phase diagram of the alloy and show that the homogeneous phase is characterized by a large amount of short-range order occurring among first-nearest neighbors. Electronic-structure calculations performed using the special quasi-random structures approach indicate that the energy gap of the alloy is rather sensitive to this short-range order.