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

Materials Modelling of π‐Phase Monochalcogenides

“…[19] This functional has demonstrated good agreement with the experimental results in determining the material structure in these systems including both lattice parameters and atomic positions as well as reasonable reproduction of the electronic band gap. Other researchers [3,4,20] have also used related GGA functionals such as PBESol and PBESol + D3, which includes dispersion corrections, and found similarly good agreement with experimental results. Other functionals, such as LDA and HSE, [21] were also used to validate our choice but did not prove to be more accurate than PBE.…”

“…The phonon spectrum of π-SnS was calculated by Skelton [3,4] et al and subsequently confirmed in Ref [32]. All phonon frequencies were found to be real, indicating the mechanical stability of the phase.…”

“…Materials modelling of the recently discovered cubic monochalcogenides, [1] also known as π-phase semiconductors, is a subject of extensive study worldwide in recent years. [2,3,4,5,6] The conventional stable phase for this group of materials is the layered orthorhombic structure with 8 atoms per unit cell with the space group Pnma, see Figure 1. Ever since the discovery of this novel cubic phase in tin monosulfide in 2015 by Rabkin et al [1] it has challenged our imagination to explore how and why such a low symmetry cubic phase consisting of 64 atoms in the unit cell is formed and what are its properties.…”

Lattice dynamics of the tin sulphides SnS2, SnS and Sn2S3: vibrational spectra and thermal transport

“…The thermoelectric performance of SnS has previously been investigated, 4 but its unfavourable electrical properties led to an averaged ZT score of 0.16, which is not competitive with either of PbTe or SnSe. 5 , 69 The π-cubic phase of SnS has an unusual band dispersion with shallow valence and conduction bands, 70 which would in principle allow for the formation of multiple “carrier pockets” on doping, 71 and in conjunction with its low thermal conductivity this may make it a good candidate thermoelectric. Sn 2 S 3 has been shown to have good electrical properties 12 and is predicted to have ambipolar dopability, 72 which, together with the very low κ latt predicted in the present calculations, suggests it too may be a good candidate thermoelectric.…”

Phase Stability of the Tin Monochalcogenides SnS and SnSe: A Quasi-Harmonic Lattice-Dynamics Study

“…[17][18][19] There has been a substantial debate in the literature over the zincblende and rocksalt phases of SnS, but zincblende SnS has been shown to be a high-energy, dynamically-unstable phase, 14,20 and reports of zincblende SnS were likely misassignments of the recently-discovered π-cubic phase. 18,21 Rocksalt SnS can be stabilised under certain conditions such as epitaxial growth, 20,22 whereas rocksalt SnSe is a dynamically stable phase under ambient conditions. 23 We therefore focus on the Pnma, Cmcm, rocksalt and π-cubic phases, the structures of which are illustrated in Figure 1.…”