Epitaxial Growth and Anomalous Hall Effect in High-Quality Altermagnetic $\alpha$-MnTe Thin Films

TL;DR

This paper demonstrates the epitaxial growth of high-quality $ ext{α}$-MnTe thin films on InP(111) substrates, revealing their anomalous Hall effect and potential for spintronics applications, thus enabling practical use of altermagnetic materials.

Contribution

It provides a detailed growth protocol and phase diagram for stabilizing pure $ ext{α}$-MnTe, and shows the films exhibit a robust anomalous Hall effect despite near-zero net magnetization.

Findings

High-quality $ ext{α}$-MnTe films grown via MBE on InP(111)

Clear phase stabilization conditions identified for pure $ ext{α}$-MnTe

Observation of anomalous Hall effect linked to Berry curvature

Abstract

The recent identification of $\alpha$-MnTe as a candidate altermagnet has attracted considerable interest, particularly for its potential application in magnetic random-access memory. However, the development of high-quality thin films - essential for practical implementation - has remained limited. Here, we report the epitaxial growth of centimeter-scale $\alpha$-MnTe thin films on InP(111) substrates via molecular beam epitaxy (MBE). Through X-ray diffraction (XRD) analysis, we construct a MnTe phase diagram that provides clear guidance for stabilizing the pure $\alpha$-MnTe phase, revealing that it is favored under high Te/Mn flux ratios and elevated growth temperatures. Cross-sectional electron microscopy confirms an atomically sharp film-substrate interface, consistent with a layer-by-layer epitaxial growth mode. Remarkably, these high-quality $\alpha$-MnTe films exhibit a pronounced anomalous Hall effect (AHE) originating from Berry curvature, despite a net magnetic moment approaching zero - a signature of robust altermagnetic character. Our work establishes a viable route for synthesizing wafer-scale $\alpha$-MnTe thin films and highlights their promise for altermagnet-based spintronics and magnetic sensing.