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arXiv · 2409.08095

Persistent quantum vibronic dynamics in a $5d^1$ double perovskite oxide

Naoya Iwahara·Jian-Rui Soh·Daigorou Hirai·Ivica Živković·Yuan Wei·Wenliang Zhang·Carlos Galdino·Tianlun Yu·Kenji Ishii·Federico Pisani·Oleg Malanyuk·Thorsten Schmitt·Henrik M Rønnow
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Abstract

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 $5d^1$ 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 $5d^1$ double perovskite, Ba$_2$CaReO$_6$, 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$_2$CaReO$_6$. Crucially, both theory and experiment demonstrate that these quantum-entangled states persist to low temperatures, despite the onset of multipolar order.

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Naoya Iwahara, Jian-Rui Soh, Daigorou Hirai, Ivica Živković, Yuan Wei, Wenliang Zhang, Carlos Galdino, Tianlun Yu, Kenji Ishii, Federico Pisani, Oleg Malanyuk, Thorsten Schmitt, Henrik M Rønnow. 2024-09-12. Persistent quantum vibronic dynamics in a $5d^1$ double perovskite oxide. https://doi.org/10.1103/vjtk-jsdg

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