Abstract:
Polar superconductors have generated significant interest as a potential route to unconventional and topological superconductivity. Strained thin films of doped strontium titanate (SrTiO3) undergo successive ferroelectric and superconducting transitions. Our experimental observations of a factor of two enhancement of the superconducting transition temperature and the fact that both ferroelectricity and superconductivity vanish around the same carrier density hint at physical interactions common to both phenomena. Many different proposals of such a link have been put forward in the theoretical literature. This talk will focus on our recent insights into both the ferroelectric and superconducting states of these films. We show that the ferroelectric transition is better described as an order-disorder transition and that local polar order persists to temperatures far above the ferroelectric transition. We discuss the mechanisms by which free carriers and dopants act to suppress the ferroelectric transition. We also discuss recent insights into the nature of the superconducting state obtained via non-reciprocal transport measurements and other properties of the superconducting state.
Bio: Susanne Stemmer is Professor of Materials at the University of California, Santa Barbara. She did her doctoral work at the Max-Planck Institute for Metals Research in Stuttgart (Germany) and received her degree from the University of Stuttgart in 1995. Her research interests are in the development of scanning transmission electron microscopy techniques, molecular beam epitaxy of oxides and topological materials, strongly correlated oxide heterostructures, and topological matter. She has authored or co-authored more than 280 publications. Honors include election to Fellow of the American Ceramic Society, Fellow of the American Physical Society, Fellow of the Materials Research Society, Fellow of the Microscopy Society of America, and a Vannevar Bush Faculty Fellowship of the Department of Defense.
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2020-09-10T14:00:002020-09-10T15:00:00CM seminar - Ferroelectric SuperconductorsEvent Information:
Abstract:
Polar superconductors have generated significant interest as a potential route to unconventional and topological superconductivity. Strained thin films of doped strontium titanate (SrTiO3) undergo successive ferroelectric and superconducting transitions. Our experimental observations of a factor of two enhancement of the superconducting transition temperature and the fact that both ferroelectricity and superconductivity vanish around the same carrier density hint at physical interactions common to both phenomena. Many different proposals of such a link have been put forward in the theoretical literature. This talk will focus on our recent insights into both the ferroelectric and superconducting states of these films. We show that the ferroelectric transition is better described as an order-disorder transition and that local polar order persists to temperatures far above the ferroelectric transition. We discuss the mechanisms by which free carriers and dopants act to suppress the ferroelectric transition. We also discuss recent insights into the nature of the superconducting state obtained via non-reciprocal transport measurements and other properties of the superconducting state.
Bio: Susanne Stemmer is Professor of Materials at the University of California, Santa Barbara. She did her doctoral work at the Max-Planck Institute for Metals Research in Stuttgart (Germany) and received her degree from the University of Stuttgart in 1995. Her research interests are in the development of scanning transmission electron microscopy techniques, molecular beam epitaxy of oxides and topological materials, strongly correlated oxide heterostructures, and topological matter. She has authored or co-authored more than 280 publications. Honors include election to Fellow of the American Ceramic Society, Fellow of the American Physical Society, Fellow of the Materials Research Society, Fellow of the Microscopy Society of America, and a Vannevar Bush Faculty Fellowship of the Department of Defense.
Event Location:
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https://ubc.zoom.us/j/61875425478?pwd=cDNjWEN1S0lZZ1BTdEpmd3ZZNVdCdz09
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