SnP₃: A Previously Unexplored Two-Dimensional Material

Abstract

We predict SnP3 to be an easily exfoliable and dynamically stable two-dimensional (2D) material with thickness-dependent electronic properties. On the basis of density functional theory calculations, we show that mono- and bilayer SnP3 has relatively low cleavage energies of 0.71 and 0.45 J m–2, lower than several other 2D materials and comparable to that of graphene (0.32 J m–2). Mono- and bilayer SnP3 have an indirect band gap of 0.83 and 0.55 eV, respectively, and the magnitude of the gap can be tuned by applying strain. Remarkably, pristine monolayer SnP3 has a relatively high carrier mobility in the range of 3000–7000 cm2 V–1 s–1, at par with well-known 2D semiconductors such as MoS2, phosphorene, and other phosphorus-based layered materials such as GeP3 and InP3. Mono- and bilayer SnP3 also show large optical absorption, resulting from the existence of the van-Hove singularities in the electronic density of states. The combined properties of layered SnP3, in particular, its high carrier mobility and tunable band gap, along with large optical absorption coefficient, open up interesting possibilities for nanoelectronic and nanophotonic applications.