Temperature- and pressure-dependent phonon transport properties of SnS across phase transition from machine-learning interatomic potential

Abstract

Recently, tin sulfide (SnS) has attracted particular attention in thermoelectrics due to its non-toxicity and earth-abundant elements. However, the phonon and thermal transport mechanisms in SnS under high temperatures and pressures are yet to be fully understood because of the strong lattice anharmonicity and structural phase transition. Herein, we construct a first-principles-based machine learning potential of SnS, which can predict the lattice dynamical evolution of the structural phase transition at different temperatures and pressures. We unveil that SnS exists an abnormal decrease of the Γ4 and Y1 phonon frequencies with increasing pressure at the low-temperature regime, which is attributed to the structural phase transition. We explore the temperature- and pressure-dependent lattice thermal conductivity of SnS. Our results pave the way for further phonon and thermal transport engineering of SnS under high temperatures and pressures.