Regular-triangle trimer and charge order preserving the Anderson condition in the pyrochlore structure of CsW<sub>2</sub>O<sub>6</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32561729.
- Also identified by DOI 10.1038/s41467-020-16873-7 and PMC identifier 7305186.
- Licence recorded as CC BY.
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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 β-pyrochlore oxide CsW<sub>2</sub>O<sub>6</sub>, where each of W 5d electrons are confined in regular-triangle W<sub>3</sub> 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 WO<sub>6</sub> 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.