Topological superconductivity and high Chern numbers in 2D ferromagnetic Shiba lattices

TL;DR

This paper explores a 2D lattice of magnetic atoms on a superconductor with spin-orbit coupling, revealing complex topological phases with high Chern numbers, and suggests experimental detection via STM spectroscopy.

Contribution

It generalizes $p_x+ip_y$ superconductivity to 2D ferromagnetic Shiba lattices and maps their topological phase diagram with high Chern numbers.

Findings

Supports a generalized $p_x+ip_y$ superconductivity in 2D ferromagnetic Shiba lattices.

Contains topological phases with Chern numbers greater than superconducting coherence length divided by lattice spacing.

Nontrivial topological signatures can be detected by STM spectroscopy in finite-size systems.

Abstract

Inspired by the recent experimental observation of topological superconductivity in ferromagnetic chains, we consider a dilute 2D lattice of magnetic atoms deposited on top of a superconducting surface with a Rashba spin-orbit coupling. We show that the studied system supports a generalization of $p_x+ip_y$ superconductivity and that its topological phase diagram contains Chern numbers higher than $\xi/a$ $(\gg1)$, where $\xi$ is the superconducting coherence length and $a$ is the distance between the magnetic atoms. The signatures of nontrivial topology can be observed by STM spectroscopy in finite-size islands.