Laboratoire Léon Brillouin, CEA Saclay, 91191 Gif sur Yvette, France
报告摘要：
In many quantum materials, strong electron correlations lead to the emergence of new states of matter. In particular, the study in the last decades of the complex phase diagram of high temperature superconducting cuprates highlighted intra-unit-cell electronic instabilities appearing at the pseudogap temperature [1]. The observed intra-unit-cell order is breaking discrete Ising-like symmetries, while preserving the lattice translation invariance. It is currently interpreted as the magnetic hallmark of loop current order, breaking both parity and time-reversal symmetries. We perform polarized neutron diffraction experiments in underdoped and detwinned YBa2Cu3O6.6 sample, that indicate a hidden local magnetic quadrupling (2x2) of the unit cell at short range [2]. Together with the intra-unit-cell order, these new results suggest a real space hidden magnetic texture of the CuO2 unit cells hosting loop currents.
[1] Ph. Bourges et al., Comptes Rendus Physique S22, 1-25 (2021).
[2] D. Bounoua et al., Comm. Phys 5, 268 (2022); Phys. Rev. B 108, 214408 (2023).
报告人简介：
Philippe Bourges is a distinguished scientist (PhD in 1989 at University of Rennes and habilitation in 2003 at University of Orsay in France). He is the group leader of superconductivity and neutron scattering at Laboratoire Léon Brillouin at CEA Saclay.He has a long track record about neutron scattering studies in condensed matter with more than 200 publications and 10000 citations with numerous works on high temperature copper-oxide superconductors. He discovered a novel magnetic order in 2006 establishing the concept of loop current. This work was awarded in 2020 by the “Science and Innovation” prize of the French Academy of Sciences. In parallel, he has been involved in the development of neutron spectroscopy instrumentation, in particular the use of polarized neutron diffraction, and the building of the future spectroscopy instrument BIFROST at the European Spallation Source (ESS) in Lund (Sweden).
报告地点：M236会议室
联系人：李源 研究员