Quantum anomalous vortex and Majorana zero mode in iron-based superconductor Fe(Te,Se)

TL;DR

This paper demonstrates that magnetic impurities in Fe(Te,Se) superconductors can create quantum anomalous vortices supporting Majorana zero modes, advancing topological quantum computing platforms.

Contribution

It introduces the concept of quantum anomalous vortices in s-wave superconductors with strong spin-orbit coupling and links them to observed Majorana modes in Fe(Te,Se).

Findings

Magnetic impurities induce topological vortices without external fields.

Observed zero-energy states are consistent with Majorana zero modes.

Quantum anomalous vortices offer new platforms for quantum computing.

Abstract

In topological insulators doped with magnetic ions, spin-orbit coupling and ferromagnetism give rise to the quantum anomalous Hall effect. Here we show that in s-wave superconductors with strong spin-orbit coupling, magnetic impurity ions can generate topological vortices in the absence of external magnetic fields. Such vortices, dubbed quantum anomalous vortices, support robust Majorana zero-energy modes when superconductivity is induced in the topological surface states. We demonstrate that the zero-energy bound states observed in Fe(Te,Se) superconductors are possible realizations of the Majorana zero modes in quantum anomalous vortices produced by the interstitial magnetic Fe. The quantum anomalous vortex matter not only advances fundamental understandings of topological defect excitations of Cooper pairing, but also provides new and advantageous platforms for manipulating Majorana zero modes in quantum computing.