ARPES study of the Mn-Bi-Te natural heterostructural families*

Magnetic Topological Insulators (MTI) are a group of quantum materials that combine non-trivial band topology and magnetic order, making them candidates for hosting quantum phenomena such as the quantum anomalous Hall Effect, axion insulator state, and quantum magnetoelectric effect. The first candidate for an intrinsic MTI is MnBi2Te4, a material made up of van der Waals-bonded septuple layers, with Mn atoms providing anti-ferromagnetic order below the Neel temperature of 25 K. For this talk, I present and discuss angle-resolved photoemission spectroscopy (ARPES) measurements on MnBi2Te4 and related natural heterostructure compounds. In MnBi2Te4, the evolution of bulk conduction bands and the topological surface state is observed above and below the Neel temperature. In the ARPES measurements, different photon energies appear to select between bulk and surface bands, assisting the use of two-dimensional fitting procedures to help quantify the effect of magnetic order on the bands at the Dirac point.