Current at a distance and resonant transparency in Weyl semi-metals
This event is part of the Biophysics/Condensed Matter Seminar Series.
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 semi-metal. Surface Fermi arcs are the most prominent manifestation of the topological nature of Weyl semi- metals. In the presence of a static magnetic eld oriented perpendicular to the sample surface, their existence leads to unique inter-surface cyclotron orbits. We show how these inter-surface cyclotron orbits aect the electronic properties of Weyl semi-metals already at the semi-classical level. As a result, we are able to propose two experiments which directly probe the Fermi arcs: a magnetic eld dependent non-local DC voltage and sharp resonances in the transmission of electromagnetic waves at frequencies controlled by the eld. We show that these experiments do not rely on quantum me- chanical phase coherence, which renders them far more robust and experimentally accessible than quantum eects. We also comment on the applicability of these ideas to Dirac semimetals.  Y. Baum, E. Berg, S.A. Parameswaran and A. Stern, \Current at a distance and resonant transparency in Weyl semi-metals", cond-mat arXiv:1508.03047 (2015).