Ferromagnetic MnSn monolayer epitaxially grown on silicon substrate

TL;DR

This paper reports the successful epitaxial growth of a ferromagnetic MnSn monolayer on silicon, demonstrating tunable Curie temperatures and a compatible interface, advancing 2D ferromagnetic materials for spintronics applications.

Contribution

First demonstration of epitaxial MnSn monolayer growth on silicon with controlled thickness and ferromagnetic properties at cryogenic temperatures.

Findings

Ferromagnetism observed with Tc ~54 K in monolayer.

Tc increases to ~235 K in 4-layer MnSn.

Epitaxial interface is atomically sharp and compatible with silicon.

Abstract

Two-dimensional (2D) ferromagnetic materials have been exhibiting promising potential in applications, such as spintronics devices. To grow epitaxial magnetic films on silicon substrate, in the single-layer limit, is practically important but challenging. In this study, we realized the epitaxial growth of MnSn monolayer on Si(111) substrate, with an atomically thin Sn/Si(111)-$2\sqrt{3}\times2\sqrt{3}$- buffer layer, and controlled the MnSn thickness with atomic-layer precision. We discovered the ferromagnetism in MnSn monolayer with the Curie temperature (Tc) of ~54 K. As the MnSn film is grown to 4 monolayers, Tc increases accordingly to ~235 K. The lattice of the epitaxial MnSn monolayer as well as the Sn/Si(111)-$2\sqrt{3}\times2\sqrt{3}$ is perfectly compatible with silicon, and thus an sharp interface is formed between MnSn, Sn and Si. This system provides a new platform for exploring the 2D ferromagnetism, integrating magnetic monolayers into silicon-based technology, and engineering the spintronics heterostructures.