Surface-sensitive electronic structure of kagome superconductor CsV₃Sb₅

We systematically study the electronic structure of a kagome superconductor CsV₃Sb₅ at different temperatures covering both its charge density wave state and normal state with angle-resolved photoemission spectroscopy. We observe that the V-shaped band around $\overline{\Gamma }$ shows three different behaviors, referred to as α/α′, β and γ, mainly at different temperatures. Detailed investigations confirm that these bands are all from the same bulk Sb-p_z origin, but they are quite sensitive to the sample surface conditions mainly modulated by temperature. Thus, the intriguing temperature dependent electronic behavior of the band near $\overline{\Gamma }$ is affected by the sample surface condition, rather than intrinsic electronic behavior originating from the phase transition. Our result systematically reveals the confusing electronic structure behavior of the energy bands around $\overline{\Gamma }$, facilitating further exploration of the novel properties in this material.