Novel two-dimensional Janus β-GeXY (X/Y = S, Se, Te) structures: first-principles examinations.

Two-dimensional (2D) structures can stably exist in different allotropes. In this manuscript, we propose a new series of Janus structures based on the β-phase of germanium monochalcogenides, namely, β-GeXY (X/Y = S, Se, and Te) monolayers. Our calculations indicate that Janus β-GeXY monolayers have a stable crystal structure and possess anisotropic mechanical properties.