Modeling the ternary chalcogenide NaMoSe from first-principles.

In the ongoing pursuit of inorganic compounds suitable for solid-state devices, transition metal chalcogenides have received heightened attention due to their physical and chemical properties. Recently, alkali-ion transition metal chalcogenides have been explored as promising candidates to be applied in optoelectronics, photovoltaics and energy storage devices. In this work, we present a theoretical study of sodium molybdenum selenide (NaMoSe). First-principles computations were performed on a set of hypothetical crystal structures to determine the ground state and electronic properties of NaMoSe. We find that the equilibrium structure of NaMoSe is a simple orthorhombic (oP) lattice, with space group Pnma, as evidenced by thermodynamics. Finally, meta-GGA computations were performed to model the band structure of oP NaMoSe at a predictive level. We employ the Tran-Blaha modified Becke-Johnson potential to demonstrate that oP NaMoSe has a direct bandgap at the Γ point that is suitable for optoelectronics. Our results provide a foundation for future studies concerned with the modeling of inorganic and hybrid organic-inorganic materials chemically analogous to NaMoSe.