Spectral study of the interplay among lattice, spin, and electron degrees of freedom in a strong correlated polar metal*

The interplay between spin-orbital coupling and structural inversion symmetry breaking in solid states has attracted a lot of interest due to non-trivial electronic and magnetic ground states. Such phenomena are typically observed in compounds of heavy elements in the transitional metal section where large atomic number gives rise to strong spin-orbital coupling. A previous study [1] has reported magnetic anisotropy driven by reconfiguration of electronic properties near Fermi surface at spin reorientation temperature. Here we demonstrate for the oxide compound Ca₃Ru₂O₇ strong correlation among phononic properties, electron reconstruction, and spin reorientation due to spin-orbital coupling and strong electron-phonon correlation. Specifically, strong renormalization of two phonon modes observed experimentally and from the first principle. Our result suggests Raman spectroscopy is a sensitive tool to fermiology changes in strong correlated systems.

[1] Markovic, I. et al. P Natl Acad Sci USA 117, 15524-15529 (2020)