seed projects

Xiaojia Wang, Bharat Jalan: Ultrafast Thermal Characterization of Complex Oxide Thin Films and Heterostructures

Complex materials with perovskite heterostructures exhibit unprecedented optical, thermal, piezoelectric, and mechanical properties, making them promising candidates for applications in spintronics, ferroelectrics, thermoelectrics, and piezoelectrics. Such extraordinary properties of perovskites are extremely sensitive to stoichiometric composition, structural defects, interface properties, and external stimuli. Thus, understanding the structure-property correlation is crucial to advance the applications of this important class of materials.

The goal of this seed proposal is to explore the possibilities of using ultrafast thermal characterization (thermal conductivity) to evaluate structural defects of epitaxially grown perovskite oxide thin films and heterostructures (specifically point defects). As a model materials system, Jalan will grow Ba_1-xSr_xSnO₃ films with controlled amounts of intrinsic (cation/anion vacancy) and extrinsic defects (doping/alloying) using a hybrid molecular beam epitaxy (MBE) approach. Wang will employ time-domain thermoreflectance (TDTR) to probe the thermal conductivities of these perovskites at different temperatures, and explore the fundamental phonon transport mechanisms in this class of materials to extract structural information such as point defects.

Funded by the National Science Foundation through the University of Minnesota MRSEC under Award Number DMR-1420013