Abstract
The tin monochalcogenides SnS and SnSe adopt four different crystal structures, viz. orthorhombic Pnma and Cmcm and
cubic rocksalt and π (𝑃2#3) phases, each of which has optimal properties for a range of potential applications. This rich
phase space makes it challenging to identify the conditions under which the different phases are obtained. We have
performed firstprinciples quasiharmonic latticedynamics calculations to assess the relative stabilities of the four phases
of SnS and SnSe. We investigate dynamical stability through the presence or absence of imaginary modes in the phonon
dispersion curves, and we compute Helmholtz and Gibbs free energies to evaluate the thermodynamic stability. We also
consider applied pressures up to 15 GPa to obtain simulated temperaturepressure phase diagrams. Finally, the relationships
between the orthorhombic crystal phases are investigated by explicitly mapping the potentialenergy surfaces along the
imaginary harmonic phonon modes in the Cmcm phase, and the relationships between the cubic phases are found by
transitionstate modelling using the climbingimage nudged elasticband method.
cubic rocksalt and π (𝑃2#3) phases, each of which has optimal properties for a range of potential applications. This rich
phase space makes it challenging to identify the conditions under which the different phases are obtained. We have
performed firstprinciples quasiharmonic latticedynamics calculations to assess the relative stabilities of the four phases
of SnS and SnSe. We investigate dynamical stability through the presence or absence of imaginary modes in the phonon
dispersion curves, and we compute Helmholtz and Gibbs free energies to evaluate the thermodynamic stability. We also
consider applied pressures up to 15 GPa to obtain simulated temperaturepressure phase diagrams. Finally, the relationships
between the orthorhombic crystal phases are investigated by explicitly mapping the potentialenergy surfaces along the
imaginary harmonic phonon modes in the Cmcm phase, and the relationships between the cubic phases are found by
transitionstate modelling using the climbingimage nudged elasticband method.
Original language  English 

Journal  Physical Chemistry Chemical Physics 
Publication status  Published  2021 
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Data for: Phase stability of the tin monochalcogenides SnS and SnSe: a quasiharmonic latticedynamics study
Skelton, J. (Creator) & Pallikara, I. (Contributor), Mendeley Data, 20 Jun 2023
DOI: 10.17632/fsghbfmj4w.1, https://data.mendeley.com/datasets/fsghbfmj4w
Dataset