Dr. Yuan Li obtained his B.S. degrees from Peking University in 2004 and Ph.D. degree from Stanford University in 2010. From 2010 to 2012, he was a Humboldt Research Fellow at the Max Planck Institute for Solid State Research, Germany. Since 2012 he has been working at the International Center for Quantum Materials, Peking University, and received tenure in 2018. Dr. Li’s research interests include phase behaviors and elementary excitations in correlated-electron materials. To determine these fundamental properties, his research group employs a broad range of scattering methods including neutron and X-ray scattering at public research facilities, as well as in-house Raman spectroscopy.
High-Tc cuprate superconductors are well-known for their antiferromagnetism inherited from the Mott-insulating parent compounds. Visible (Raman) and invisible (X-ray) photon scattering experiments, in particular those that utilize resonant enhancement, allow us to probe dynamic antiferromagnetic spin correlations with excellent sensitivity. In this talk, I will present results obtained by applying these combined methods to the first two members of the Hg-family of cuprates, Hg1201 and Hg1212. The central finding may be regarded as a magnon counterpart of the isotope effect in conventional superconductors: the single- and bi-magnon energies are found to undergo significant increases from Hg1201 to Hg1212 that correlate with the rises in the superconducting energy gap and Tc. Together with superconductivity’s feedback on the spin excitations, these results strongly support a magnetic pairing mechanism.
邀 请 人：方 辰（电话：8264 9073）
联 系 人：李园园（电话：8264 9364）