The impact of twin boundaries on thermal transport in Bi₂Te₃

Advancing beyond the current state-of-the-art nanostructured thermoelectric materials requires a detailed understanding of the impact of interfaces on their thermal properties. In this work, we utilise reverse non-equilibrium molecular dynamics (rNEMD) simulations, with a recently developed empirical interatomic potential [1], to elucidate the impact of specific twin boundary structures on thermal transport in bismuth telluride (Bi₂Te₃). Three basal plane twin boundaries and the 60° twin boundary [2] are investigated. The interfacial thermal resistance is calculated, along with an analysis of the structural changes observed at interfaces. We find that interfacial thermal resistance increases with decreasing stability of the interface, suggesting that the most effective interfaces may require more effort to fabricate. A comparison of the properties of these four twin boundaries is carried out, enabling us to identify those that may be the most impactful in terms of suppressing lattice thermal conductivity at room temperature.

[1] B. Huang et al., J. Phys. D Appl. Phys. 52, 425303 (2019)
[2] K. Kim et al., Nat. Commun. 7, 1-6 (2016)