Molecular dynamics investigation of the thermal conductivity of ternary silicon-germanium-tin alloys

A further reduction of the thermal conductivity (kappa) of silicon-germanium (SiGe) alloys is indispensable for their use as thermoelectric materials. Thus far, heteroatom-doped and nanostructured SiGe systems have been mainly synthesized and tested. This work presents a possibility of reducing the kappa of SiGe by alloying with tin (Sn). Our molecular dynamics simulations predict that the kappa of ternary SiGeSn alloys can be 40% lower than those of binary SiGe and GeSn alloys due mainly to increased mass disorder scattering of phonons. Our findings provide insight into the mechanism of kappa suppression in multielement alloys and guidance on how to design them for thermoelectric applications.