[1Ca02-12] SS1

[1Ca03S] Electronic structure and magnetic properties of magnetic topological sandwich structures

*Ryushiro Fukushima¹, Kazuki Sumida², Yukiharu Takeda², Satoru Ichinokura¹, Toru Hirahara¹ (1. Tokyo Institute of Technology, 2. JAEA-SPring-8)

Topological insulators (TI) are insulating in the bulk but have metallic spin-polarized edge (surface) states. This surface state has a linear type dispersion called the Dirac cone. By inducing magnetism in TI, a Dirac cone gap opens and the Quantum anomalous Hall effect (QAHE), in which the Hall resistance is quantized at zero field, can occur. In the magnetic topological insulator heterostructure, a gap opens at the surface Dirac cone, but a gapless state remains at the interface with the substrate, which hinders the appearance of the QAHE. Therefore, it is necessary to develop the heterostructure into a sandwich structure and to create a ferromagnetic layer on the bottom surface as well. However, the interaction between the two magnetic layers is still unknown. In this study, we investigated the electronic state and magnetization properties of the sandwich structure by Angle-resolved Photoemission Spectroscopy (ARPES) and X-ray Magnetic Circular Dichroism (XMCD) measurements.