  Quasi-two-dimensional kagome metals AV3Sb5 (A = K, Rb, and Cs) have attracted
much recent interest due to exotic quantum phenomena such as unconventional
superconductivity, topological charge order and giant anomalous Hall effect.
Here we report pressure-induced reemergent superconductivity in CsV3Sb5 by
electrical transport measurements under high pressures up to 47.9 GPa. We show
that the superconducting critical temperature Tc is first enhanced by pressure
and reaches its first maximum ~ 8.9 K at 0.8 GPa, then the Tc is suppressed by
pressure and cannot be detected above 7.5 GPa, forming a dome-shaped
superconducting phase diagram. Remarkably, upon further compression above 16.5
GPa, a new superconducting state arises, of which Tc is enhanced by pressure to
a second maximum ~ 5.0 K and the reemergent superconductivity keeps robust up
to 47.9 GPa. Combined with high-pressure synchrotron x-ray diffraction
measurements that demonstrate the stability of the pristine hexagonal phase up
to 43.1 GPa, we suggest that the reemergence of superconductivity in the
V-based superconductor could be attributed to a pressure-induced Lifshitz
transition.
