Metastable cubic tin sulfide: A novel phonon-stable chiral semiconductor

SnS is a semiconductor of interest for next-generation thin-film photovoltaic devices. The ground-state phase is layered with an orthorhombic (Pnma) crystal structure. Anisotropy in the electrical properties has been linked to the low performance of SnS solar cells. These factors make a new cubic phase (π-SnS) of immense practical interest. We report the properties of the recently solved crystal structure (P213) of cubic SnS from first-principles. π-SnS is phonon stable, in contrast to the zincblende phase, and lies 2.2 kJ/mol above the ground state. It features an electronic bandgap of 1.7 eV with a chiral modulation of the band-edge states.