Predicted Binary Compounds of Tin and Sulfur

Three
known binary compounds of tin (Sn) and sulfur (S), namely,
SnS, SnS2, and Sn2S3, have been extensively
studied for potential application in energy generation and conversion
applications. Inspired by the existence of many metastable phases
of SnS, we explore the chemical space of nine crystalline solids with
chemical composition SnxS1–x (x falls between 0.25 and 0.75),
predicting that Sn3S is thermodynamically stable in a metallic Pmn21 phase. Due to the layered structure of
this phase, Sn3S is a quasi two-dimensional material, characterized
by highly anisotropic electronic-related properties. Moreover, the
discovered metastable structures of Sn3S2, Sn2S, and Sn5S2 are just about 5 meV/atom
above the stability limit, and may potentially be realized. The data
set of 369 low-energy structures of nine SnxS1–x crystalline solids
reported in this work is a reliable sample of the low-energy sector
of the chemical space, and thus being useful for the currently established
materials databases, providing a playground for future data-mining
works in materials discoveries.