  In kagome metals AV3Sb5 (A = K, Rb, Cs), three-dimensional charge order
(3D-CO) is the primary instability that sets the stage for other collective
orders to emerge, including unidirectional stripe order, orbital flux order,
electronic nematicity, and superconductivity. Here, we use high-resolution
angle-resolved photoemission spectroscopy to determine the microscopic
structure of three-dimensional charge order (3D-CO) in AV3Sb5 and its interplay
with superconductivity. Our approach is based on identifying an unusual
splitting of kagome bands induced by 3D-CO, which provides a sensitive way to
refine the spatial charge patterns in neighboring kagome planes. We found a
marked dependence of the 3D-CO structure on composition and doping. The
observed difference between CsV3Sb5 and the other compounds potentially
underpins the double-dome superconductivity in CsV3(Sb,Sn)5 and the suppression
of Tc in KV3Sb5 and RbV3Sb5. Our results provide fresh insights into the rich
phase diagram of AV3Sb5.
