Exploring the Epitaxial Growth Kinetics and Anomalous Hall Effect in Magnetic Topological Insulator MnBiTe Films.

The discovery of MnBiTe-based intrinsic magnetic topological insulators has fueled tremendous interest in condensed matter physics, owing to their potential as an ideal platform for exploring the quantum anomalous Hall effect and other magnetism-topology interactions. However, the fabrication of single-phase MnBiTe films remains a common challenge in the research field. Herein, we present an effective and simple approach for fabricating high-quality, near-stoichiometric MnBiTe films by directly matching the growth rates of intermediate BiTe and MnTe. Through systematic experimental studies and thermodynamic calculations, we demonstrate that binary phases of BiTe and MnTe are easily formed during film growth, and the reaction of BiTe + MnTe → MnBiTe represents the rate-limiting step among all possible reaction paths, which could result in the presence of BiTe and MnTe impurity phases in the grown MnBiTe films. Moreover, BiTe and MnTe impurities introduce negative and positive anomalous Hall (AH) components, respectively, in the AH signals of MnBiTe films. Our work suggests that further manipulation of growth parameters should be the essential route for fabricating phase-pure MnBiTe films.