[NCNR/NIST] Mn-uniformity in Intrinsically Magnetic Topological Insulator Superlattices

In order to realize quantum-mechanical electrical properties at high-temperature in industrially scalable systems, it is highly desirable that we should identify materials which posses the targeted behaviors intrinsically. MnBi2Te4 (MBT) is the lone example of an instrinsically antiferromagnetically ordered topological insulator which can realize the quantum anomalous hall effect without doping or other chemical/structural modification. However, the experimentally reported behavior in MBT single crystals and thin films varies widely, and is thought to relate to Mn-deficiency. Here, we systematically examine the role of Mn content and mobility through the growth of MBT/MnTe superlattices of varying MnTe thickness. We propose to use neutron reflectometry to probe interface roughness and Mn-migration in these superlattices.