Coexistence of two intertwined charge density waves in a kagome system

The recently discovered AV3Sb5 (A=K, Rb, Cs) family, possessing V kagome nets, has received considerable attention due to the topological electronic structure and intriguing correlated phenomena, including an exotic charge density wave (CDW) superconductivity. Detailed studies are essential unravel characteristics origin of CDW as well its interplay with Here, we present angle-resolved photoemission spectroscopy (ARPES) measurements for CsV3Sb5 at multiple temperatures photon energies reveal nature from perspective. We evidence a three-dimensional (3D) order. In process also pinpoint surface state attributed Cs terminated surface. This was previously band folding along c direction or quantum confinement. expected 2-fold lattice reconstruction axis is observed be quadrupling unit cell, thus first time directly demonstrating 3D Moreover, this configuration originates two distinct types distortions in adjacent layers. These results not only provide key insights into unconventional but provides important reference further on relationship between