Helical and topological phase detection based on nonlocal conductance measurements in a three terminal junction

Abstract

The helical state is a fundamental prerequisite for many spintronics applications and Majorana zero mode engineering in nanoscopic semiconductors. Its existence in quasi-one-dimensional nanowires was predicted to be detectable as a characteristic reentrant behavior in the conductance, which in a typical two-terminal architecture may be difficult to distinguish from other possible phenomena such as Fabry-Perot oscillations. Here we present an alternative method of helical gap detection free of the mentioned ambiguity, and based on the nonlocal conductance measurements in a three-terminal junction. We find that the interplay between the spin-orbit coupling and the perpendicular magnetic field leads to a spin-dependent trajectory of electrons and as a consequence a preferential injection of electrons in one of the arms. This causes a remarkable enhancement of nonlocal conductance in the helical gap regime. We show that this phenomenon can be also used to detect the topological superconducting phase when the junction is partially proximitized by an s-wave superconductor.

8 pages, 9 figures

References in corpus (12)

• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
• Coherent control of a single electron spin with electric fields
• Hard gap in epitaxial semiconductor-superconductor nanowires
• SNS junctions in nanowires with spin-orbit coupling: role of confinement and helicity on the sub-gap spectrum
• Andreev rectifier: a nonlocal conductance signature of topological phase transitions
• Conductance behavior in nanowires with spin-orbit interaction -- A numerical study
• Quantum-Dot Parity Effects in Trivial and Topological Josephson Junctions
• Dynamic response functions and helical gaps in interacting Rashba nanowires with and without magnetic fields
• Anisotropy of the spin-orbit coupling driven by a magnetic field in InAs nanowires
• Renormalization of the Majorana bound state decay length in a perpendicular magnetic field
• Spin filtering effect generated by the inter-subband spin-orbit coupling in the bilayer nanowire with the quantum point contact