Non-local effects in Weyl semi-metals
Abstract: Topology in various guises plays a central role in modern condensed matter physics. Although the original applications of topological ideas to band structures relied on the existence of a fully gapped bulk spectrum, more recently it has been recognized that protected surface states can arise even in gapless systems. The prototypical example of a gapless topological phase is a Weyl semimetal.
Surface Fermi arcs are the most prominent manifestation of the topological nature of Weyl semimetals. In the presence of a static magnetic field oriented perpendicular to the sample surface, their existence leads to unique inter-surface cyclotron orbits. We demonstrate that in the presence of such a field, the unusual inter-surface cyclotron orbits on the Fermi arcs lead to the generation of a non-local current across the extent of a sample.
As a result, we are able to propose several experiments which directly probe the Fermi arcs: a magnetic field dependent non-local DC voltage, sharp resonances in the transmission of electromagnetic waves and non-local Coulomb Drag.