Surface-sensitive electronic structure of kagome superconductor CsV₃Sb₅

Abstract We systematically study the electronic structure of a kagome superconductor CsV 3 Sb 5 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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mi>Γ</mml:mi> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:math> 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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mi>Γ</mml:mi> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:math> 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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mi>Γ</mml:mi> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:math> , facilitating further exploration of the novel properties in this material.