Rich nature of Van Hove singularities in Kagome superconductor CsV3Sb5

The layered kagome metals AV3Sb5 (A = K, Rb, Cs) exhibit correlated phenomena intertwined with a topological electronic structure and van Hove singularities (VHSs) near the Fermi level. This study combines polarization-dependent angle-resolved photoemission spectroscopy (ARPES) with density functional theory (DFT) to reveal the sublattice properties of 3d-orbital VHSs in CsV3Sb5. Four VHSs are identified around the M point, three near the Fermi level; two are sublattice-pure, one sublattice-mixed. A higher-order VHS is found just below the Fermi level. Intensity modulation of Dirac cones around K demonstrates sublattice interference. These insights provide a foundation for understanding correlation phenomena in AV3Sb5.

Yong Hu, Xianxin Wu, Brenden R. Ortiz, Sailong Ju, Xinloong Han, Junzhang Ma, Nicholas C. Plumb, Milan Radovic, Ronny Thomale, Stephen D. Wilson, Andreas P. Schnyder, Ming Shi