Temperature-driven reorganization of electronic order in CsV${}_3$Sb${}_5$

Abstract

We report a temperature dependent x-ray diffraction study of the electronic ordering instabilities in the kagome material CsV${}_3$Sb${}_5$. Our measurements between 10 K and 120 K reveal an unexpected reorganization of the three-dimensional electronic order in the bulk of CsV${}_3$Sb${}_5$: At 10 K, a 2x2x2 superstructure modulation due to electronic order is observed, which upon warming changes to a 2x2x4 superstructure at 60 K. The electronic order-order transition discovered here involves a change in the stacking of electronically ordered V${}_3$Sb${}_5$-layers and agrees perfectly with anomalies previously observed in magneto-transport measurements. This implies that the temperature dependent three-dimensional electronic order plays a decisive role for transport properties, which are related to the Berry-curvature of the V-bands. Our data also show that the bulk electronic order in CsV${}_3$Sb${}_5$ breaks the 6-fold rotational symmetry of the underlying $P6/mmm$ lattice structure.

5 pages, 3 figures