Supporting data for Temperature-dependent thermal conductivity of MBE-grown epitaxial SrSnO₃ films

Abstract

This work studies the temperature-dependent thermal properties of a single crystalline SSO thin film prepared with hybrid molecular beam epitaxy. By combining time-domain thermoreflectance and Debye–Callaway modeling, physical insight into thermal transport mechanisms is provided. At room temperature, the 350-nm SSO film has a thermal conductivity of 4.4 W m¯¹ K¯¹ , ∼60% lower than those of other perovskite oxides (SrTiO₃, BaSnO₃) with the same ABO₃ structural formula. This difference is attributed to the low zone-boundary frequency of SSO, resulting from its distorted orthorhombic structure with tilted octahedra. At high temperatures, the thermal conductivity of SSO decreases with temperature following a ∼T ¯⁰∙⁵⁴ dependence, weaker than the typical T¯¹ trend dominated by the Umklapp scattering. Corresponding author for STEM data is K. Andre Mkhoyan. Corresponding author for film growth and XRD data is Bharat Jalan. Corresponding author for TDTR data is Xiaojia Wang.