Suppressed thermal conductivity of bilayer SnS: A comparative study among the monolayer, bilayer and bulk SnS

Abstract

The layer-stacking of 2D materials have been proven to be an effective tool to modulate the low-dimensional electronic structures and transport properties. In this study, the lattice thermal transport properties of bilayer SnS are investigated systematically by solving phonon Boltzmann transport equation based on first-principles calculations. The stacking effect on the in-plane thermal conductivity is further revealed through comparing phonon transport properties of the monolayer, bilayer and bulk SnS. A dramatic suppression of the thermal conductivity, even below 0.5 Wm −1 K −1 per layer at 300 K, can be observed for the fully relaxed bilayer SnS, which implies the great potential for SnS-based thermoelectric applications. The underlying phonon transport mechanisms are also uncovered, and the drop of phonon relaxation time, resulted from the enhanced interlayer anharmonic phonon scattering, is responsible for the suppression of lattice thermal transport. • The stacking stability of bilayer SnS is revealed, and the AA′-stacking is the most dynamically stable configuration for the bilayer SnS. • A dramatically suppressed thermal conductivity for the special stacking configuration of the bilayer SnS, e. g. 0.294 (0.112) Wm −1 K −1 per layer at 300 K along the zigzag (armchair) direction, can be predicted. • The underlying phonon transport mechanisms, and the stacking effects, are also revealed through a comparative study among the monolayer, bilayer and bulk SnS.