主讲人：李世燕 教授（复旦大学）

题目：Evidence for Gapless Quantum Spin Liquid in a Honeycomb lattice

时间：2023年05月25日（周四）上午09：00

地点： 理工楼1226会议室

邀请人：赵继泽

报告摘要：

One important issue in current condensed matter physics is the search of quantum spin liquid (QSL), an exotic magnetic state with strongly-fluctuating and highly-entangled spins down to zero temperature without static order. However, there is no consensus on the existence of a QSL state in any real material so far, due to the inevitable disorders and competing exchange interactions on frustrated spin lattices. Here we report systematic heat transport measurements on a honeycomb-lattice compound BaCo2(AsO4)2, which manifests magnetic order in zero field. In a narrow in-plane field range after the magnetic order is nearly suppressed, in both perpendicular and parallel to the zigzag direction, a finite residual linear term of thermal conductivity is clearly observed, which is attributed to mobile fractionalized spinon excitations. This provides smoking-gun evidence for a gapless QSL state in BaCo2(AsO4)2[1].

[1]C. P. Tu et al., arXiv:2212.07322 (2022).

个人简介：

李世燕教授于1997年和2002年在中国科学技术大学获得学士和博士学位，之后在加拿大多伦多大学和舍布鲁克大学做博士后研究，2007年加入复旦大学。他目前的研究兴趣是超导体、量子自旋液体、拓扑材料等量子材料, 擅长极低温输运及热力学性质测量。已发表论文130余篇，包括PRL/PRX 24篇，Nature子刊7篇、PNAS 2篇，JACS两篇。他获得了2015年度马丁伍德中国物理科学奖，入选了上海市“东方学者”、基金委优青、教育部长江学者特聘教授。