Generic Helical Liquids in 2D Topological Insulators: Transport Properties and Applications
Research Project
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01.09.2015
- 31.07.2017
This research proposal focuses on the investigation of electronic transport properties ofmetallic helical edge states of two-dimensional topological insulators. The objectives canbe divided into two major parts.The first part is devoted to the investigation of fundamental properties of the helical liquids.In a recent paper [Schmidt et al., Phys. Rev. Lett. 108, 156402 (2012)], we introduced theconcept of a generic helical liquid (GHL). This is the most general model of a time-reversalinvariant helical liquid without axial spin symmetry. This symmetry is usually broken inexperimental realizations, and we showed that its absence changes the transport propertiessignificantly. In the first part of this project, we will investigate transport properties ofinteracting GHLs in the presence of disorder, the effect of a weak breaking of time-reversalsymmetry, and we will develop proposals on how to measure the spin structure of the helicaledge states.The second part focuses on nanostructured geometries of two-dimensional topologicalinsulators which can be realized in experiments and allow a more detailed characterizationof the properties of GHLs. In particular, we shall examine antidots, which are coupled bytunnelling to the edges of the sample. We shall use a combination of numerical and analytictechniques to determine the current through such an antidot. We expect it to display adistinctive interference pattern which is unique to GHLs. Moreover, we shall investigate therole of the charging energy on the antidot and the possible emergence of the Kondo effect.
