Pressure-induced Lifshitz transition in Cs V 3 Sb 5 evidenced by the quantum oscillation measurements

Cs V 3 Sb 5 exhibits a unique double-dome superconducting phase diagram under pressure, closely linked to its distinctive charge density wave (CDW) order evolution and corresponding Fermi surface reconstruction. The intricate interplay between CDW and superconductivity has garnered significant research interest, particularly in finding experimental methods to investigate Fermi surface evolution under pressure. Here, by measuring the quantum oscillation signals in in-plane resistivity and thermoelectric effect of Cs V 3 Sb 5 at various pressures, we reveal for the first time that the Fermi surface of Cs V 3 Sb 5 undergoes an abrupt change around 0.4 GPa. This phenomenon may be associated with alterations in the interlayer modulation within the CDW state, which is consistent with our density functional theory calculations. Furthermore, we observe the presence of a Dirac band that may moves away from the Fermi energy as pressure increases. Our findings offer crucial insights into the Fermi surface evolution of Cs V 3 Sb 5 under pressure.