Zero-field topological Hall effect in BiSb/MnGa bi-layers as a signature of ground-state skyrmions at room temperature

TL;DR

This study demonstrates the existence of thermodynamically stable skyrmions at room temperature in BiSb/MnGa bi-layers, evidenced by the zero-field topological Hall effect, and highlights the role of interfacial DMI in their stabilization.

Contribution

It provides experimental evidence of room-temperature stable skyrmions in BiSb/MnGa bi-layers using THE and shows how interfacial DMI can be tailored through annealing.

Findings

Observation of zero-field THE indicating stable skyrmions at room temperature.

Interfacial DMI energy can be controlled by annealing temperature.

Skyrmions are thermodynamically stable without external magnetic fields.

Abstract

We observe the signature of zero-field ground-state skyrmions in BiSb topological insulator / MnGa bi-layers by using the topological Hall effect (THE). We observe a large critical interfacial Dzyaloshinskii-Moriya-Interaction energy (5.0 pJ/m) at the BiSb/MnGa interface that can be tailored by controlling the annealing temperature of the MnGa template. The THE was observed at room temperature even under absence of an external magnetic field, which gives the strong evidence for the existence of thermodynamically stable skyrmions in MnGa/BiSb bi-layers. Our results will give insight into the role of interfacial DMI tailored by suitable material choice and growth technique for generation of stable skyrmions at room temperature.