学术报告（2022年11月22日10：00）：Possible Kitaev Magnets with 3d Electrons: Hope, Reality and Opportunity

主持人： 王猛  教授

报告简介：Magnetism in cobalt compounds has an interesting facet due to the element’s non-negligible spin-orbit interplay. In recent years, several cobalt oxides with layered honeycomb crystal structures have been proposed to have the potential to realize the celebrated Kitaev model for quantum spin liquids. For this reason, they are becoming intensively studied as 3d-electron analogues of 5d iridates and 4d α-RuCl3. From a crystal grower and spectroscopist’s view point, I will present our study on two of these compounds: Na2Co2TeO6 (NCTO) and Na3Co2SbO6 (NCSO), which look similar at first sight. Our data suggest that subtle differences make the two systems highly contrasting against each other: NCTO has a nominally C3-symmetric crystal structure, whereas NCSO is monoclinic; NCTO is more antiferromagnetic than NCSO, probably due to further-neighbor interactions. At the end of the day, the two systems might not be very close to the idealized Kitaev model, but are nonetheless highly interesting. Experimental hints at realizing novel quantum magnetism will be discussed, along with open issues.

报告人简介：Yuan Li received his B.S. degrees from Peking University in 2004, and Ph.D. degree from Stanford University in 2010. He was a Humboldt Research Fellow at the Max Planck Institute for Solid State Research, Germany, from 2010 to 2012. Since 2012, he has been working as an associate professor at the International Center for Quantum Materials, Peking University, where he received tenure in 2018. His research involves state-of-the-art crystal growth and the use of scattering spectroscopy, in particular neutron and photon scattering, for studying the structure and dynamics of materials with strong electron correlation and novel quasiparticle excitations. He has been selected for an elite research program supported by the MOST of China and a recipient of Sir Martin Wood China Prize.