Tin and germanium monochalcogenide binary compounds, M(=Ge,Sn)X(=S,Se), are earth-abundant, low-toxicity material families relevant for electronic applications.

Typically orthorhombic in structure,  very recently they have been found to present multiple novel phases with new functional properties at the nanoscale.

These new phases belong to an extended family of metastable phases in the bulk.

Since they have been synthesised experimentally, it was hypothesised that they are stabilised as nanometric particles by size effects, or by solution ligands, or by the substrate surface.

To identify the controlling mechanisms in the stabilisation of metastable phases, we modelled the surface energies, effects of ligand absorption, and the interactions with substrate surfaces, focusing on the low-symmetry cubic-pi- and gamma- phases of SnS and SnSe.

Our results explain the experimental conditions and elucidate the role of ligands and substrate effects on these processes. This approach can help design ab initio syntheses of metastable phases.

E. Segev et al., CrystEngComm 20, 4237 (2018)

R.E. Abutbul et al., Nanoscale 11, 17104 (2019)

R.E. Abutbul et al. ACS Crystal Growth & Design 22,4366 (2022)

N. Mishra et al. ACS Crystal Growth and Design 23, 2301 (2023)

N. Zakay et al. ACS Applied Materials and Interfaces 15,15668(2023)

N. Zakay et al. Mater. Chem. Front. (2023)