大会議室 (Main Conference room of Faculty of Science) 16:00 -17:00 of Friday, 22 July 2016
Prof. Henrik M. Rønnow, Head of Laboratory for Quantum Magnetism – LQM, École Polytechnique Fédérale de Lausanne – EPFL (Visitor Centre for Emergent Matter Science, RIKEN, President for Swiss Neutron Scattering Society – SGN)
Title: Hubbard heritage in undoped cuprates – and conjecture for finding new superconductors
Neutron Spectroscopy is a powerful technique to measure magnetic excitation spectra. I will present how neutron spectroscopy allow us to reach very detailed understanding of the 2D Heisenberg antiferromagnet and how this model is derived from the Hubbard model at half filling. This allowed establishing a unified one-band hubbard model for a series of undoped cuprates, and allowed developing a new theory that suggests fractionalization of spin-waves into deconfined spinons at high energy. In the second part I will show how neutron spectroscopy reveals similarities between cuprates and iron based superconductors and present a conjecture for how to find new superconductors with the aid of next generation neutron spectrometers (CAMEA), allowing spectroscopy from sub-mm3 crystals.
Contact person, Yoshihiro Kubozono (RIIS) ex 7850