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arXiv · 2312.01767

Spectroscopic signatures and origin of a hidden order in Ba$_2$MgReO$_6$

Jian-Rui Soh·Maximilian E. Merkel·Leonid Pourovskii·Ivica Živković·Oleg Malanyuk·Jana Pásztorová·Sonia Francoual·Daigorou Hirai·Andrea Urru·Davor Tolj·Dario Fiore-Mosca·Oleg Yazyev·Nicola A. Spaldin·Claude Ederer·Henrik M. Rønnow
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Abstract

Clarifying the underlying mechanisms that govern ordering transitions in condensed matter systems is crucial for comprehending emergent properties and phenomena. While transitions are often classified as electronically driven or lattice-driven, we present a departure from this conventional paradigm in the case of the double perovskite Ba$_2$MgReO$_6$. Leveraging resonant and non-resonant elastic x-ray scattering techniques, we unveil the simultaneous ordering of structural distortions and charge quadrupoles at a critical temperature of $T_\mathrm{q}$$\sim$33 K. Using a variety of complementary first-principles-based computational techniques, we demonstrate that while electronic interactions drive the ordering at $T_\mathrm{q}$, it is ultimately the lattice that dictates the specific ground state that emerges. Our findings highlight the crucial interplay between electronic and lattice degrees of freedom, providing a unified framework to understand and predict unconventional emergent phenomena in quantum materials.

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Jian-Rui Soh, Maximilian E. Merkel, Leonid Pourovskii, Ivica Živković, Oleg Malanyuk, Jana Pásztorová, Sonia Francoual, Daigorou Hirai, Andrea Urru, Davor Tolj, Dario Fiore-Mosca, Oleg Yazyev, Nicola A. Spaldin, Claude Ederer, Henrik M. Rønnow. 2023-12-04. Spectroscopic signatures and origin of a hidden order in Ba$_2$MgReO$_6$. https://arxiv.org/abs/2312.01767

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