Low-dissipation edge currents without edge states
ORAL
Abstract
We show that bulk free carriers in topologically trivial multi-valley insulators with non-vanishing Berry curvature give rise to low-dissipation edge currents, which are squeezed within a distance of the order of the valley diffusion length from the edge. This happens even in the absence of edge states [topological (gapless) or otherwise], and when the bulk equilibrium carrier concentration is thermally activated across the gap.
Physically, the squeezed edge current arises from the spatially inhomogeneous orbital magnetization that develops from valley-density accumulation near the edge. While this current possesses neither topology nor symmetry protection and, as a result, is not immune to dissipation, in clean enough devices it can mimic low-loss ballistic transport.
Physically, the squeezed edge current arises from the spatially inhomogeneous orbital magnetization that develops from valley-density accumulation near the edge. While this current possesses neither topology nor symmetry protection and, as a result, is not immune to dissipation, in clean enough devices it can mimic low-loss ballistic transport.
*J.C.W.S. was supported by the Singapore National Research Foundation (NRF) under NRF fellowship award NRF-NRFF2016-05.
G.V. was supported by NSF Grant DMR-1406568.
–
Presenters
-
Giovanni Vignale
- University of Missouri
- Department of Physics and Astronomy, University of Missouri
- University of Missouri (USA) & Yale-NUS College (Singapore)