Manipulation of Majorana fermion, Andreev reflection and Josephson current on topological insulators

TL;DR

This paper theoretically investigates charge transport in topological insulator-based junctions, revealing that Majorana modes and Josephson currents are highly sensitive to magnetization direction, with tunable phase shifts.

Contribution

It introduces a novel analysis of Majorana fermion manipulation and Josephson effect control on topological insulators with magnetic interfaces.

Findings

Majorana modes are sensitive to magnetization direction.

Josephson current phase shift can be continuously tuned.

Magnetization orientation significantly affects charge transport.

Abstract

We study theoretically charge transport properties of normal metal (N) / ferromagnet insulator (FI) / superconductor (S) junction and S/FI/S junction formed on the surface of three-dimensional topological insulator (TI), where chiral Majorana mode (CMM) exists at FI/S interface. We find that CMM generated in N/FI/S and S/FI/S junctions are very sensitively controlled by the direction of the magnetization ${\bm m}$ in FI region. Especially, the current-phase relation of Josephson current in S/FI/S junctions has a phase shift neither 0 nor $\pi$, which can be tuned continuously by the component of ${\bm m}$ perpendicular to the interface.