Angle-resolved photoemission spectroscopy study of the Möbius Kondo insulator candidate CeRhSb

Abstract

The electronic structure of a M\"obius Kondo insulator candidate of CeRhSb has been investigated by employing angle-resolved photoemission spectroscopy, density functional theory (DFT) band calculations, and dynamical mean-field theory (DMFT) band calculations. Fermi surfaces (FSs) and band structures are successfully measured for three orthogonal crystallographic directions. A sharp Ce $4f$ peak is observed at the Fermi level (${E}_{\text{F}}$), and its temperature ($T$) evolution agrees with that of the Ce $4f$ Kondo resonance. The metallic FSs are obtained for all three different (100), (010), and (001) planes. The Ce $4f$ FSs are described properly by the unfolded DFT calculations considering the reduced Ce-only unit cell. The $T$ dependence of Ce $4f$ states as well as the dispersive coherent Ce $4f$ bands are described well by the DMFT calculations and reveal the anisotropic $c\text{\ensuremath{-}}f$ hybridization. The photon energy dependence of the Fermi-edge states in CeRhSb reveals the three-dimensional character, consistent with the bulk states dispersing to ${E}_{\text{F}}$ over a larger energy scale rather than the predicted M\"obius topological surface states.