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Zeitschriftenartikel:

L. Pourovskii, S. Khmelevskyi:
"Hidden order and multipolar exchange striction in a correlated f-electron system.";
Proceedings of the National Academy of Science of the USA, 118 (2021), S. e202531711.



Kurzfassung englisch:
The nature of order in low-temperature phases of some mate-
rials is not directly seen by experiment. Such "hidden orders"
(HOs) may inspire decades of research to identify the mechanism
underlying those exotic states of matter. In insulators, HO phases
originate in degenerate many-electron states on localized f or
d shells that may harbor high-rank multipole moments. Coupled
by intersite exchange, those moments form a vast space of com-
peting order parameters. Here, we show how the ground-state
order and magnetic excitations of a prototypical HO system, nep-
tunium dioxide NpO2, can be fully described by a low-energy
Hamiltonian derived by a many-body ab initio force theorem
method. Superexchange interactions between the lowest crystal-
field quadruplet of Np4+ ions induce a primary noncollinear order
of time-odd rank 5 (triakontadipolar) moments with a secondary
quadrupole order preserving the cubic symmetry of NpO2. Our
study also reveals an unconventional multipolar exchange stric-
tion mechanism behind the anomalous volume contraction of the
NpO2 HO phase.


Elektronische Version der Publikation:
https://publik.tuwien.ac.at/files/publik_302150.pdf


Erstellt aus der Publikationsdatenbank der Technischen Universität Wien.