Center for Artificial Low Dimensional Electronic Systems

Towards topological superconductivity and Majoranamodes in a 2D topological insulator

Vlad Pribiag

June 7(Tue) - June 7(Tue), 2016

Title: Towards topological superconductivity and Majoranamodes in a 2D

topological insulator

Speaker: Prof. Vlad Pribiag (School of Physics and Astronomy, University of Minnesota)

Topological insulators are characterized by boundary modes with very strong spin-momentum coupling. In proximity to a conventional superconductor, these modes are predicted to host topological superconductivity, an exotic state of matter that supports Majoranazero-modes. Localized Majoranamodes obey non-Abelian exchange statistics, making them interesting building blocks for topological quantum computing. In this talk, I will describe our current efforts to realize topological superconductivity in nanostructures based on InAs/GaSbquantum wells, a two-dimensional topological insulator (2D TI). By electrostatically-gating the devices we observe superconducting transport in all three regimes of the 2D TI: bulk electrons, edge modes and bulk holes. We use superconducting quantum interference measurements as a sensitive method for determining the spatial distribution of the supercurrentin each regime. These measurements reveal a clear transition from bulk-to edge-dominated supercurrentunder conditions of high bulk resistivity, which we associate with the 2D topological phase. These experiments establish InAs/GaSbas a promising platform for observing Majoranasmodes and probing their exchange statistics.

References: [1] L. Fu and C. L. Kane, Physical Review B 79, 161408(R) (2009)

[2] J. Alicea, Reports on Progress in Physics 75, 076501 (2012)

[3] V. S. Pribiaget al., Nature Nanotechnology 10, 593-598 (2015)