Strained hexagonal ScN: A material with unusual structural and optical properties

Local-density approximation calculations are performed to predict properties of compressively strained hexagonal ScN. This material is found to exhibit a large electromechanical response, a structural phase transition from a nonpolar to a polar structure, and a variation of the band gap in the entire visible light range when continuously changing the compressive strain. Microscopic effects responsible for these anomalies are revealed and discussed. Suggestions on how to practically grow ScN-based materials having such unusual properties are also provided.