Quantum Magnetism - neutrons in the quasi-particle zoo with Henrik M Rønnow
Speaker: Prof Henrik M. Rønnow, EPFL
Abstract: The field of quantum magnetism form an arena where theoretical models and experiments on real materials meet to further our understanding of quantum many body physics. I will illustrate the unique role of neutron scattering through results on selected Cu2+ based materials serving as physical realizations of fundamental low-dimensional spin ½ models. Balancing the borderline between classical antiferromagnetic order and quantum fluctuating ground states, in some ways, theoretical description of fully quantum ground states as found in spin chains and ladders is currently more advanced than for ordered spin clusters, or even the simple 2D square lattice. The antiferromagnetically ordered unfrustrated 2D square lattice host behaviour not explainable by spin-wave theory. Finally I will show how magnetic excitations can now also be investigated with high-resolution Resonant Inelastic X-ray Scattering (RIXS).
Biography: Prof. Henrik M. Rønnow is an associate professor at EPFL's Faculty of Basic Sciences, where he founded the Laboratory for Quantum Magnetism (LQM) in 2007. He earned his PhD from the University of Copenhagen in 2000 and has held research positions at CEA-Grenoble, NEC Laboratories (Princeton), the James Franck Institute (Chicago), the London Centre for Nanotechnology, the Paul Scherrer Institut and ETH Zurich.
His research focuses on quantum magnetism and strongly correlated electron phenomena, spanning high-temperature superconductors, CMR manganites and skyrmion-hosting materials, with pioneering contributions to the study of magnetic skyrmions. He also invented the CAMEA neutron spectrometer concept, now in operation at the Paul Scherrer Institut and under construction at the European Spallation Source. He has authored over 200 publications with more than 5,000 citations.