MSE Seminar: “Controlling ferroelectricity at the nanoscale: from oxide heterostructures to freestanding crystalline membranes”

Complex oxides are fascinating material systems exhibiting a diverse set of electrical, magnetic, and thermal properties. In particular, ferroelectric oxides with an electrically switchable polarization and large dielectric and piezoelectric responses are considered as critical components for next-generation low-power logic devices, non-volatile memories, and nanoscale sensors and actuators, etc. Recent advances in thin-film synthesis techniques including the synthesis of oxide heterostructures and crystalline membranes have provided opportunities for realizing novel functionality in ferroelectrics. In this talk, I will show the ability to enable new device capabilities and emergent properties in the oxide heterostructures and crystalline membranes. First, I will introduce the kinetic control of ferroelectric switching pathways to create multiple non-volatile polarization states in (111)-oriented PbZr0.2Ti0.8O3/SrTiO3 heterostructures. Such switching phenomena transcend the bi-stability of ferroelectric polarization and hold promise for multi-state functional applications. Second, I will introduce our discovery of strain-induced ferroelectricity in quantum paraelectric SrTiO3 crystalline membranes, which reveals enormous potential of employing membranes to create and enhance ferroelectricity in environmentally