Condensed Matter Physics Seminar: Christian Spånslätt Rugarn

Abstract: The composition of one-dimensional edge modes at the boundary of two-dimensional of topological states of matter, such as the quantum Hall states, is crucial for understanding their low-energy transport properties. In turn, this understanding is pivotal in many situations, e.g., for using edge states to detect and manipulate anyons: exotic excitations that are neither fermions nor bosons.

Whereas the most studied edges have modes propagating only in one direction (called “downstream”), many states are predicted to host modes propagating also in the opposite (“upstream”) direction. However, identifying the presence of such modes is a very challenging task, since equilibration effects due to edge disorder tend to cause all charge current to flow downstream, thereby obscuring possible contributions of upstream modes.

In this talk, I describe why and how thermal edge transport is a powerful tool to overcome this problem. I also present selected results from recent theoretical and experimental efforts to pin-point various complex edge structures, including those of exotic non-Abelian nature. These results highlight a rich interplay between topology and thermal transport in experimentally accessible devices.