Resonant inelastic X-rays scattering from the square-lattice compounds Sr2RuO4 (left) yield detailed maps of electronic excitations as a function of energy E and momentum Q (right) (Credit: © Max Planck Institute for Solid State Research)
Conduction electrons in quantum materials form delocalised states that can be quantum-coherent over macroscopic length scales while being subject to local interactions akin to those in atomic physics. This dichotomy spawns a large variety of collective quantum phenomena and remains one of the major challenges of modern condensed matter physics. Now a group of researchers, headed by Prof. Bernhard Keimer from the Max Planck Institute for Solid State Research in Stuttgart, have tackled this problem and published their findings in the journal of Nature Communications.
The team used the tender X-ray RIXS instrument at the PETRA III beamline P01 to study in details the electronic excitations in the square-lattice compound Sr2RuO4. This material has long served as a model system for the influence of atomic-scale correlations on the macroscopic electronic properties – including particularly the unconventional superconducting state that forms at low temperatures. In their study, the momentum-space maps, acquired with a high-resolution RIXS spectrometer, display clear fingerprints of the separation of energy scales for spin and orbital correlations which can be attributed to interactions akin to Hund’s rules in atomic physics. These new results will serve as a testbed for state-of-the-art many-body theories and could possibly yield fresh insight into the origin of superconductivity in Sr2RuO4.
The work involved also a team of scientists from DESY, the Max Planck Institute for Chemical Physics of Solids (Germany), Örebro University (Sweden), Friedrich-Alexander-University, University of Paris-Saclay (France), Flatiron Institute (USA) and Tohoku University (Japan).
(Partly from News MPI Stuttgart)
Reference:
H. Suzuki, L. Wang, J. Bertinshaw, H.U.R. Strand, S. Käser, M. Krautloher, Z. Yang, N. Wentzell, O. Parcollet, F. Jerzembeck, N. Kikugawa, A.P. Mackenzie, A. Georges, P. Hansmann, H. Gretarsson, B. Keimer, Distinct spin and orbital dynamics in Sr2RuO4, Nat. Commun. (2023), DOI: 10.1038/s41467-023-42804-3
