Metallic surface states in a correlated d-electron topological Kondo insulator candidate FeSb <sub>2</sub>
Ke-Jun Xu, Su-Di Chen, Yu He, Jun-Feng He, Shujie Tang, Chunjing Jia, Yue Ma, Sung‐Kwan Mo, Dong-Hui Lu, Makoto Hashimoto, Thomas Devereaux, Zhi‐Xun Shen
Abstract
Significance The correlation-driven topological insulator is a poorly understood state of matter where topological protection is afforded in the absence of well-defined quasiparticles. Ongoing research is hampered by the scarcity of model material families, consisting of only the 4f rare-earth boride compounds thus far. Here we establish a class of candidate topological Kondo insulator in FeSb 2 , based on 3d electrons instead of 4f electrons. Comparison between the different families will allow identification of key ingredients responsible for the exotic insulating state. Our band-structure measurements will serve as important guides for theoretical modeling of the correlated insulating state in this system.