Possible star-of-David pattern charge density wave with additional modulation in the kagome superconductor CsV3Sb5

AV(3)Sb(5) (A = K, Rb, Cs) is a novel kagome superconductor coexisting with the charge density wave (CDW) order. Identifying the structure of the CDW order is crucial for understanding the exotic normal state and superconductivity in this system. Here, we report V-51 nuclear magnetic resonance (NMR) and Sb-121/123 nuclear quadrupole resonance (NQR) studies on kagome-metal CsV3Sb5. Below the CDW transition temperature T-CDW similar to 98 K, an abrupt change of spectra was observed, indicating that the transition is of the first order. By further analyzing the spectra, we find that the CDW order is commensurate. And most remarkably, the obtained experimental results suggest that the charge modulation of the CDW order is of star-of-David pattern and accompanied by an additional charge modulation in bulk below T* similar to 40 K. Our results revealing the unconventional CDW order provide new insights into AV(3)Sb(5).

Automated summary

In this study, the CDW order structure in the kagome superconductor CsV3Sb5 is investigated. It is found that the CDW order is of the first order, commensurate, and exhibits a star-of-David pattern. The experimental results provide new insights into AV(3)Sb(5).