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.

Presenters

  • Giovanni Vignale

    University of Missouri, Department of Physics and Astronomy, University of Missouri, University of Missouri (USA) & Yale-NUS College (Singapore)

Authors

  • Giovanni Vignale

    University of Missouri, Department of Physics and Astronomy, University of Missouri, University of Missouri (USA) & Yale-NUS College (Singapore)

  • Justin C. W. Song

    Division of Physics and Applied Physics, Nanyang Technological University