  Since the discovery of a new family of vanadium-based kagome superconductor
AV3Sb5 (A=K, Rb, and Cs) with topological band structures, extensive effort has
been devoted to exploring the origin of superconducting states and the
intertwined orders. Meanwhile, searching for new types of superconductors with
novel physical properties and higher superconducting transition temperatures
has always been a major thread in the history of superconductor research. Here
we report a successful fabrication and the topological states of a
Titanium-based kagome metal CsTi3Bi5 (CT3B5) crystal. The as-grown CT3B5
crystal is of high quality and possesses a perfect two-dimensional kagome net
of Titanium. The superconductivity of the CT3B5 crystal shows that the critical
temperature Tc is of ~4.8 K. First-principle calculations predict that the
CT3B5 has robust topological surface states, implying that CT3B5 is a Z2
topological kagome superconductor. This finding provides a new type of
superconductors and the base for exploring the origin of superconductivity and
topological states in kagome superconductors.
