title: Robust transport signatures of topological superconductivity in topological insulator nanowires.
abstract: Finding a clear signature of topological superconductivity in transport experiments remains an outstanding challenge. In this work, we propose exploiting the unique properties of three-dimensional topological insulator nanowires to generate a normal-superconductor junction in the single-mode regime where an exactly quantized 2e2/h zero-bias conductance can be observed over a wide range of realistic system parameters. This is achieved by inducing superconductivity in half of the wire, which can be tuned at will from trivial to topological with a parallel magnetic field, while a perpendicular field is used to gap out the normal part, except for two spatially separated chiral channels. The combination of chiral mode transport and perfect Andreev reflection makes the measurement robust to moderate disorder, and the quantization of conductance survives to much higher temperatures than in tunnel junction experiments. Our proposal may be understood as a variant of a Majorana interferometer which is easily realizable in experiments.
authors.affiliation: Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA and Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: Fernando
authors.initials: F
authors.lastname: de Juan
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: Roni
authors.initials: R
authors.lastname: Ilan
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA and Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, 01187 Dresden, Germany.
authors.forename: Jens H
authors.initials: JH
authors.lastname: Bardarson