# Novel Majorana mode and magnetoresistance in ferromagnetic superconducting topological insulator

## TL;DR

This paper theoretically explores how coexistence of ferromagnetism and superconductivity on the surface of a topological insulator influences Majorana modes and magnetoresistance, revealing magnetization-dependent effects on tunneling conductance.

## Contribution

It introduces a novel analysis of Majorana mode sensitivity to magnetization in ferromagnetic-superconducting topological insulators, highlighting controllable magnetoresistance effects.

## Key findings

- Majorana mode energy depends on ferromagnetic magnetization magnitude.
- Superconducting gap renormalization affects Andreev reflection and tunneling conductance.
- Antiparallel magnetization configuration induces tunable magnetoresistance.

## Abstract

Among the potential applications of topological insulators, we investigate theoretically the effect of coexistence of proximity-induced ferromagnetism and superconductivity on the surface states of 3-dimensional topological insulator, where the superconducting electron-hole excitations can be significantly affected by the magnetization of ferromagnetic order. We find that, Majorana mode energy, as a verified feature of TI F/S structure, along the interface sensitively depends on the magnitude of magnetization $m_{zfs}$ in FS region, while its slope in perpendicular incidence presents steep and no change. Since the superconducting gap is renormalized by a factor $\eta(m_{zfs})$, hence Andreev reflection is more or less suppressed, and, in particular, resulting subgap tunneling conductance is more sensitive to the magnitude of magnetizations in FS and F regions. Furthermore, an interesting scenario happens at the antiparallel configuration of magnetizations $m_{zf}$ and $m_{zfs}$ resulting in magnetoresistance in N/F/FS junction, which can be controlled and decreased by tuning the magnetization magnitude in FS region.