Magneto-conductance of topological junctions based on two-dimensional electron gases reveals Majorana phases

TL;DR

This paper investigates how magnetic fields and spin-orbit effects influence the conductance in 2DEG-based junctions, revealing topological phases hosting Majorana modes through quantized conductance plateaus.

Contribution

It introduces the consideration of magneto-orbital and transverse Rashba spin-orbit effects in modeling 2DEG junctions, demonstrating their role in topological phase transitions and Majorana mode signatures.

Findings

Magnetic field induces topological phase transitions with Majorana modes.

Quantized conductance plateaus indicate Majorana phases at low chemical potential.

Anomalous magneto-conductance occurs in wide junctions or high chemical potentials.

Abstract

We calculate the linear conductance of a two-dimensional electron gas (2DEG)-based junction between a normal semiconductor section and a hybrid semiconductor-superconductor section, under perpendicular magnetic field. We consider two important terms often neglected in the literature, the magneto-orbital and transverse Rashba spin-orbit. The strong orbital effect due to the magnetic field yields topological phase transitions to nontrivial phases hosting Majorana modes in the hybrid section. The presence of a potential barrier at the junction interface reveals the Majorana phases as quantized plateaus of high conductance, for low values of the chemical potential. In wide junctions (or large chemical potentials) the phase transitions occur at low magnetic fields but the magneto-conductance becomes anomalous and lacks clearly quantized plateaus.