Understanding and tailoring thermal transport properties of perovskite oxide thin films

Perovskite oxides have been extensively used in electronic, photovoltaic, and piezoelectric applications, owing to their remarkable ability to be fine-tuned in terms of structures, compositions, and properties. In the realm of semiconducting-oxide-based electronic devices, understanding and tailoring the thermal transport properties of perovskite oxides are of critical importance to meet specific needs, including heat dissipation, thermal switches, and energy conversion and storage. In this talk, I will share our recent progress in utilizing the ultrafast pump-probe metrology to study and engineer the thermal transport properties of two model materials of perovskite oxides. The first material is La_0.5Sr_0.5CoO_3-δ (LSCO) thin films, where we demonstrate a continuous tuning of the thermal conductivity of LSCO by a factor of over 5 using electrolyte gating at room temperature. The second material is SrSnO₃ (SSO), as an emerging ultra-wide bandgap material for power electronics. The impact of anharmonicity, due to the distorted orthorhombic structure of SSO with tilted SnO₆ octahedra, on the temperature-dependent thermal conductivity of SSO will be discussed. The structure-thermal property relationships of LSCO and SSO obtained from these studies enable us to engineer and optimize functional materials based on perovskite oxides, thereby, fostering their applications across a wide spectrum.