3 years ago

Hallmarks of Hunds coupling in the Mott insulator Ca2RuO4

Hallmarks of Hunds coupling in the Mott insulator Ca2RuO4
M. Kim, Y. Sassa, E. Rotenberg, J. Chang, T. K. Kim, H. M. Rønnow, D. Sutter, C. G. Fatuzzo, S. Moser, F. Cossalter, M. Grioni, A. Bostwick, T-R Chang, N. C. Plumb, H-T Jeng, C. Jozwiak, A. Georges, V. Granata, T. Neupert, M. Shi, C. E. Matt, R. Fittipaldi, A. Vecchione, G. Gatti, M. Hoesch
A paradigmatic case of multi-band Mott physics including spin-orbit and Hund’s coupling is realized in Ca2RuO4. Progress in understanding the nature of this Mott insulating phase has been impeded by the lack of knowledge about the low-energy electronic structure. Here we provide—using angle-resolved photoemission electron spectroscopy—the band structure of the paramagnetic insulating phase of Ca2RuO4 and show how it features several distinct energy scales. Comparison to a simple analysis of atomic multiplets provides a quantitative estimate of the Hund’s coupling J=0.4 eV. Furthermore, the experimental spectra are in good agreement with electronic structure calculations performed with Dynamical Mean-Field Theory. The crystal field stabilization of the dxy orbital due to c-axis contraction is shown to be essential to explain the insulating phase. These results underscore the importance of multi-band physics, Coulomb interaction and Hund’s coupling that together generate the Mott insulating state of Ca2RuO4.

Publisher URL: http://www.nature.com/articles/ncomms15176

DOI: 10.1038/ncomms15176

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.