Pourovskii, L. V., & Khmelevskyi, S. (2019). Quadrupolar superexchange interactions, multipolar order, and magnetic phase transition in UO₂. Physical Review B, 99(9), Article 094439. https://doi.org/10.1103/physrevb.99.094439
E134-01 - Forschungsbereich Applied and Computational Physics
-
Zeitschrift:
Physical Review B
-
ISSN:
2469-9950
-
Datum (veröffentlicht):
1-Mär-2019
-
Umfang:
8
-
Verlag:
AMER PHYSICAL SOC
-
Peer Reviewed:
Ja
-
Keywords:
Quadrupolar superexchange interactions; magnetic phase transition; multipolar order
en
Abstract:
The origin of noncollinear magnetic order in UO2 is studied by an ab initio dynamical-mean-field-theory framework in conjunction with a linear-response approach for evaluating intersite superexchange interactions between U5f2 shells. The calculated quadrupole-quadruple superexchange interactions are found to unambiguously resolve the frustration of face-centered-cubic U sublattice toward stabilization of the experimentally observed noncollinear 3k-magnetic order. Therefore, the exotic 3k-antiferromagnetic order in UO2 can be accounted for by a purely electronic exchange mechanism acting in the undistorted cubic lattice structure. The quadrupolar short-range order above magnetic ordering temperature TN is found to qualitatively differ from the long-range order below TN.
