Polymorph-dependent band-gap nature in La2O2S: Newly synthesized direct-gap oA phase, indirect-gap hP phase, and a pressure-driven hP → oA transition

Key Points

• The study identifies both direct-gap and indirect-gap phases in La2O2S polymorphs, enhancing application potential.
• Measurements show distinct band gaps, with the newly synthesized oA phase exhibiting a direct gap while hP is indirect.
• Investigation uses pressure to induce the transition from the hP to oA phase in La2O2S, showcasing polymorph versatility.
• Findings highlight the necessity for further exploration of pressure effects on band-gap properties in these materials.