Activities
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flatbands as an arena for designing superconducting and topological systems
Hideo Aoki
University of Tokyo, Japan
12 October 2021 Tue 5 pm
IBS Center for Theoretical Physics of Complex Systems (PCS), Administrative Office (B349), Theory Wing, 3rd floor
Expo-ro 55, Yuseong-gu, Daejeon, South Korea, 34126 Tel: +82-42-878-8633
One novel arena for designing superconductors and topological systems is the flat-band systems. A basic idea is that flat bands give unique opportunities for realising peculiar pairing on the one hand, and for realising topological states on the other. If we turn to non-equilibrium, we have even more versatile opportunities. This talk theoretically gives an overview of these, embracing superconductivity and topology in and out of equilibrium. I'll start with superconductivity, where I examine flat single- and multi-band models, where they are both shown to have unusual pairing properties, leading us beyond the conventional "nesting" physics[1]. A totally different way to make the system
topological is to illuminate the system with circularly-polarised light. The resulting "Floquet topological insulator" is indeed a prototype of nonequilibrium-induced quantum states. This avenue is then extended to flat-band systems. I'll finally combine the above, which culminates to "Floquet topological superconductivity"[2].
[1] H. Aoki, J. Superconductivity and Novel Magnetism 33, 2341 (2020).