Molecular Beam Epitaxy Growth of [CrGe/MnGe/FeGe] Superlattices: Toward Artificial B20 Skyrmion Materials with Tunable Interactions

TL;DR

This paper reports the successful growth of epitaxial B20 superlattices of FeGe, MnGe, and CrGe using molecular beam epitaxy, enabling systematic tuning of magnetic interactions crucial for skyrmion-based applications.

Contribution

It introduces a new class of artificial skyrmion materials—B20 superlattices—whose parameters can be systematically controlled, advancing the development of tunable skyrmion systems.

Findings

Successful growth of single-crystal B20 superlattices on Si(111)

High-quality interfaces with low intermixing confirmed by STEM and EDS

Potential for tunable skyrmion properties in engineered superlattices

Abstract

Skyrmions are localized magnetic spin textures whose stability has been shown theoretically to depend on material parameters including bulk Dresselhaus spin orbit coupling (SOC), interfacial Rashba SOC, and magnetic anisotropy. Here, we establish the growth of a new class of artificial skyrmion materials, namely B20 superlattices, where these parameters could be systematically tuned. Specifically, we report the successful growth of B20 superlattices comprised of single crystal thin films of FeGe, MnGe, and CrGe on Si(111) substrates. Thin films and superlattices are grown by molecular beam epitaxy and are characterized through a combination of reflection high energy electron diffraction, x-ray diffraction, and cross-sectional scanning transmission electron microscopy (STEM). X-ray energy dispersive spectroscopy (XEDS) distinguishes layers by elemental mapping and indicates good interface quality with relatively low levels of intermixing in the [CrGe/MnGe/FeGe] superlattice. This demonstration of epitaxial, single-crystalline B20 superlattices is a significant advance toward tunable skyrmion systems for fundamental scientific studies and applications in magnetic storage and logic.