Resonating holes vs molecular spin-orbit coupled states in group-5 lacunar spinels.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37633997.
- Also identified by DOI 10.1038/s41467-023-40811-y and PMC identifier 10460446.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The valence electronic structure of magnetic centers is one of the factors that determines the characteristics of a magnet. This may refer to orbital degeneracy, as for j<sub>eff</sub> = 1/2 Kitaev magnets, or near-degeneracy, e.g., involving the third and fourth shells in cuprate superconductors. Here we explore the inner structure of magnetic moments in group-5 lacunar spinels, fascinating materials featuring multisite magnetic units in the form of tetrahedral tetramers. Our quantum chemical analysis reveals a very colorful landscape, much richer than the single-electron, single-configuration description applied so far to all group-5 GaM<sub>4</sub>X<sub>8</sub> chalcogenides, and clarifies the basic multiorbital correlations on M<sub>4</sub> tetrahedral clusters: while for V strong correlations yield a wave-function that can be well described in terms of four V<sup>4+</sup>V<sup>3+</sup>V<sup>3+</sup>V<sup>3+</sup> resonant valence structures, for Nb and Ta a picture of dressed molecular-orbital j<sub>eff</sub> = 3/2 entities is more appropriate. These internal degrees of freedom likely shape vibronic couplings, phase transitions, and the magneto-electric properties in each of these systems.