Regular-triangle trimer and charge order preserving the Anderson condition in the pyrochlore structure of CsW₂O₆.

ABSTRACT: Since the discovery of the Verwey transition in magnetite, transition metal compounds with pyrochlore structures have been intensively studied as a platform for realizing remarkable electronic phase transitions. We report on a phase transition that preserves the cubic symmetry of the ?-pyrochlore oxide CsW₂O₆, where each of W 5d electrons are confined in regular-triangle W₃ trimers. This trimer formation represents the self-organization of 5d electrons, which can be resolved into a charge order satisfying the Anderson condition in a nontrivial way, orbital order caused by the distortion of WO₆ octahedra, and the formation of a spin-singlet pair in a regular-triangle trimer. An electronic instability due to the unusual three-dimensional nesting of Fermi surfaces and the strong correlations of the 5d electrons characteristic of the pyrochlore oxides are both likely to play important roles in this charge-orbital-spin coupled phenomenon.

SUBMITTER: Okamoto Y 

PROVIDER: S-EPMC7305186 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature