Coexistence of Multiple Stacking Charge Density Waves in Kagome Superconductor ${\mathrm{C}\mathrm{s}\mathrm{V}}_3{\mathrm{S}\mathrm{b}}_5$

The recently discovered Kagome family ${\mathrm{A}\mathrm{V}}_3{\mathrm{S}\mathrm{b}}_5$ (A = K, Rb, Cs) exhibits rich physical phenomena, including non-trivial topological electronic structure, giant anomalous Hall effect, charge density waves (CDW) and superconductivity. Notably, CDW in ${\mathrm{A}\mathrm{V}}_3{\mathrm{S}\mathrm{b}}_5$ is evidenced to intertwine with its superconductivity and topology, but its nature remains elusive. Here, we combine x-ray scattering experiments and density-functional theory calculations to investigate the CDWs in ${\mathrm{C}\mathrm{s}\mathrm{V}}_3{\mathrm{S}\mathrm{b}}_5$ and demonstrate the coexistence of 2 $\times$ 2 $\times$ 2 and 2 $\times$ 2 $\times$ 4 CDW stacking phases. Competition between these CDW phases is revealed by tracking the temperature evolution of CDW intensities, which also manifests in different transition temperatures during warming- and cooling measurements. We also identify a meta-stable quenched state of ${\mathrm{C}\mathrm{s}\mathrm{V}}_3{\mathrm{S}\mathrm{b}}_5$ after fast-cooling process. Our study demonstrates the coexistence of competing CDW stacking in ${\mathrm{C}\mathrm{s}\mathrm{V}}_3{\mathrm{S}\mathrm{b}}_5$, offering new insights in understanding the novel properties of this system.