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Hallmarks of Hunds coupling in the Mott insulator Ca2RuO4

DOI: 10.1038/ncomms15176 DOI Help

Authors: D. Sutter (Universität Zürich) , C. G. Fatuzzo (Institute of Physics, École Polytechnique Fedérale de Lausanne (EPFL)) , S. Moser (Advanced Light Source (ALS)) , M. Kim (CNRS) , R. Fittipaldi (CNR-SPIN; Università di Salerno) , A. Vecchione (CNR-SPIN; Università di Salerno) , V. Granata (CNR-SPIN; Università di Salerno) , Y. Sassa (Uppsala University) , F. Cossalter (Universität Zürich) , G. Gatti (Institute of Physics, École Polytechnique Fedérale de Lausanne (EPFL)) , M. Grioni (Institute of Physics, École Polytechnique Fedérale de Lausanne (EPFL)) , H. M. Rønnow (Institute of Physics, École Polytechnique Fedérale de Lausanne (EPFL)) , N. C. Plumb (Swiss Light Source) , C. E. Matt (Swiss Light Source) , M. Shi (Swiss Light Source) , M. Hoesch (Diamond Light Source) , T. K. Kim (Diamond Light Source) , T.-R. Chang (National Tsing Hua University; National Cheng Kung University) , H.-T. Jeng (National Tsing Hua University; Academia Sinica) , C. Jozwiak (Advanced Light Source (ALS)) , A. Bostwick (Advanced Light Source (ALS)) , E. Rotenberg (Advanced Light Source (ALS)) , A. Georges (CNRS; University of Geneva) , T. Neupert (Universität Zürich) , J. Chang (Universität Zürich)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Nature Communications , VOL 8

State: Published (Approved)
Published: May 2017
Diamond Proposal Number(s): 14617 , 12926

Open Access Open Access

Abstract: 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.

Journal Keywords: Electronic properties and materials; Phase transitions and critical phenomena

Subject Areas: Physics, Materials

Instruments: I05-ARPES

Other Facilities: SIS at Swiss Light Source; MAESTRO at Advanced Light Source

Added On: 09/05/2017 09:46


Discipline Tags:

Physics Hard condensed matter - structures Materials Science

Technical Tags:

Spectroscopy Angle Resolved Photoemission Spectroscopy (ARPES)