English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

A paradigmatic case of multi-band Mott physics including spin-orbit andHund's coupling is realised in Ca$_2$RuO$_4$. Progress in understanding thenature of this Mott insulating phase has been impeded by the lack of knowledgeabout the low-energy electronic structure. Here we provide -- usingangle-resolved photoemission electron spectroscopy -- the band structure of theparamagnetic insulating phase of Ca$_2$RuO$_4$ and show how it features severaldistinct energy scales. Comparison to a simple analysis of atomic multipletsprovides a quantitative estimate of the Hund's coupling $J=0.4$ eV.Furthermore, the experimental spectra are in good agreement with electronicstructure calculations performed with Dynamical Mean-Field Theory. The crystalfield stabilisation of the d$_{xy}$ orbital due to $c$-axis contraction isshown to be important in explaining the nature of the insulating state. It isthus a combination of multiband physics, Coulomb interaction and Hund'scoupling that generates the Mott insulating state of Ca$_2$RuO$_4$. Theseresults underscore the importance of Hund's coupling in the ruthenates andrelated multiband materials.

Hallmarks of Hund's coupling in the Mott insulator Ca$_2$RuO$_4$