Pristine electronic properties in multinary semiconductor alloys at magic compositions

The materials electronic structure is usually very sensitive to topological distribution of atoms in the materials. Generally, the electronic integrity is easily destroyed by defects and disorder causing charge localization. The design of multinary materials has attracted a great interest for its wide tunability in properties. This functional versality is rooted in many-fold degrees of freedom in composition and atomic distribution. At some “magic” compositions, the disordered material system can exhibit perfect short range ordered (SRO) ionic distributions that conserve the local octet rule despite the absence of long range order. In this contribution, we study the dual sublattice mixed semiconductor alloy (ZnSnN₂)_1-x:(ZnO)_2x in which perfect SRO are observed when x=0.0 and 0.25. Disordered structures were generated from Monte Carlo simulations and the energies were calculated from first principles. At the magic composition, these SRO conserving systems have a much reduced mixing enthalpy and increased band gap. More importantly, these SRO structures do not have charge localization effects near band edges, as seen in the inverse participation ratio, thereby maintaining a pristine electronic structure.