Persistent quantum vibronic dynamics in a 5⁢𝑑1 double perovskite oxide

Quantum entanglement between the spin, orbital, and lattice degrees of freedom in condensed matter systems can emerge due to an interplay between spin-orbit and vibronic interactions. Heavy transition metal ions decorated on a face-centered-cubic lattice, for example, in 5d1 double perovskites, are particularly suited to support these quantum entangled states, but direct evidence has not yet been presented. In this work, we report additional peaks in the low-energy spectra of a 5d1 double perovskite, Ba 2 CaReO6, which cannot be explained by adopting a purely classical description of lattice vibrations. Instead, our theoretical analysis demonstrates that these spectroscopic signatures are characteristic of orbital-lattice entangled states in Ba 2 CaReO6. Crucially, both theory and experiment demonstrate that these quantum-entangled states persist to low temperatures, despite the onset of multipolar order.

https://opac.ll.chiba-u.jp/da/curator/900123456/

https://opac.ll.chiba-u.jp/da/curator/900123456/vjtk-jsdg.pdf

American Physical Society

Journal Article

Physical Review B

112

10

104104-1

104104-7

2025-09-18

https://doi.org/10.1103/vjtk-jsdg

eng

publisher

(c)2025 American Physical Society