关键词: oscillation, Fermi surface, band structure

Abstract: The kagome system has attracted great interest in condensed matter physics due to its unique structure that can host various exotic states such as superconductivity (SC), charge density waves (CDWs) and nontrivial topological states. The topological semimetal RbTi$_{3}$Bi$_{5}$ consisting of a Ti kagome layer shares a similar crystal structure to the topological correlated materials $A$V$_{3}$Sb$_{5}$ ($A = {\rm K}$, Rb, Cs) but without the absence of CDW and SC. Systematic de Haas-van Alphen oscillation measurements are performed on single crystals of RbTi$_{3}$Bi$_{5}$ to pursue nontrivial topological physics and exotic states. Combining this with theoretical calculations, the detailed Fermi surface topology and band structure are investigated. A two-dimensional Fermi pocket $\beta $ is revealed with a light effective mass, consistent with the semimetal predictions. The Landau fan diagram of RbTi$_{3}$Bi$_{5}$ reveals a zero Berry phase for the $\beta $ oscillation in contrast to that of CsTi$_{3}$Bi$_{5}$. These results suggest that kagome RbTi$_{3}$Bi$_{5 }$ is a good candidate for exploring nontrivial topological exotic states and topological correlated physics.

Key words: oscillation, Fermi surface, band structure