# Vortex bound states of charge and magnetic fluctuations-induced topological superconductors in heterostructures

## TL;DR

This paper investigates vortex bound states in topological superconductor heterostructures induced by charge and magnetic fluctuations, revealing zero-energy states that could host Majorana modes without proximity effects.

## Contribution

It introduces a minimal model for vortex states in fluctuation-induced topological superconductors, showing zero-energy bound states across different pairing symmetries.

## Key findings

- Zero-energy vortex bound states exist for all pairing symmetries.
- Majorana modes could be observed without proximity-induced superconductivity.
- Vortex states are accessible at relatively high temperatures.

## Abstract

The helical electron states on the surface of topological insulators or elemental Bismuth become unstable toward superconducting pairing formation when coupled to the charge or magnetic fluctuations. The latter gives rise to pairing instability in chiral channels $d_{xy}\pm i d_{x^2-y^2}$, as has been observed recently in epitaxial Bi/Ni bilayer system at relatively high temperature, while the former favors a pairing with zero total angular momentum. Motivated by this observation we study the vortex bound states in these superconducting states. We consider a minimal model describing the superconductivity in the presence of a vortex in the superconducting order parameter. We show that zero-energy states appear in the spectrum of the vortex core for all pairing symmetries. Our findings may facilitate the observation of Majorana modes bounded to the vortices in heterostructures with no need for a proximity-induced superconductivity and relatively large value of $\Delta/E_F$.