Day / Time
Date(s) - 07/02/2017
13 h 00 min - 14 h 30 min
Ecole de Physique, Auditoire Stueckelberg, 24 quai E. Ansermet
Prof. Justin Song
Nanyang Technological University and Institute of High Performance Computing
Berry curvature and interacting electron liquids
Abstract: The “twisting” of electron wavefunctions in crystals, as encoded by Bloch band Berry curvature or band topology, yield anomalous electronic properties that characterize topological materials. In the presence of electron interactions, a rich array of topological phases and behaviors are expected to manifest. I will detail how the combined action of Berry curvature and electron interactions dramatically alters the collective behavior of interacting electron liquids, yielding a new class of collective excitations – Berry plasmons. Berry plasmons manifest as chiral propagating plasmonic modes, which are confined to system boundaries, and appear even in the absence of magnetic field or topological edge states. They exhibit a rich phenomenology including split energy dispersions for oppositely directed plasmon modes, with splitting that depends directly on interaction strength. Berry plasmons arise generically in anomalous Hall metals, and provide a new avenue of addressing the role of interactions in topological matter. The striking signatures they possess can be probed in readily available material systems and experimental set-ups, granting a novel all-optical probe of topological bands.