Manipulation of the anomalous Hall effect in magnetic topological insulator heterostructure MnBi2Te4/Bi2Te3 by Si substrate surface engineering

We developed an in situ Hall measurement setup and measured the anomalous Hall effect (AHE) in magnetic topological insulator heterostructures MnBi2Te4/Bi2Te3 grown on different Si(111) substrate surfaces. For the sample grown on the Si(111)-7×7 surface, the AHE signal appears at 15 K and becomes larger by further cooling, showing that the Curie temperature Tc is 15 K. In contrast, although the Tc is the same, the AHE signal shows a local maximum at 10 K for the sample grown on the β-Bi/Si(111)-3×3 surface. A plausible explanation for this peculiar behavior is the enhanced skew scattering caused by the Bi layer, or the presence of the states localized at the interfacial Bi layer, which will affect the Berry curvature of the system. Our results demonstrate the possibility to artificially control the property of a two-dimensional magnet by modification of the substrate surface with a single monatomic layer.