主讲人：李伟副研究员（中国科学院理论物理研究所）

题目：Identification of Magnetic Interactions and High-field Quantum Spin Liquid in α-RuCl₃

时间：2021年7月6日（周二）下午15:00

地点：理工楼1226报告厅

联系人：赵继泽

摘要:

The frustrated magnet α-RuCl₃constitutes a fascinating quantum material platform that harbors the intriguing Kitaev physics. However, a consensus on its intricate spin interactions and field-induced quantum phases has not been reached yet. Here we exploit multiple state-of-the-art many-body methods and determine the microscopic spin model that quantitatively explains major observations in α-RuCl₃, including the zigzag order, double-peak specific heat, magnetic anisotropy, and the characteristic M-star dynamical spin structure, etc. According to our model simulations, the in-plane field drives the system into the polarized phase at about 7 T and a thermal fractionalization occurs at finite temperature, reconciling observations in different experiments. Under out-of-plane fields, the zigzag order is suppressed at 35 T, above which, and below a polarization field of 100 T level, there emerges a field-induced quantum spin liquid. The fractional entropy and algebraic low-temperature specific heat unveil the nature of a gapless spin liquid, which can be explored in high-field measurements on α-RuCl₃.

报告人简介：李伟，理论物理研究所副研究员。2006年本科毕业于北航，2011年博士毕业于中国科学院，2012-2015年在德国慕尼黑大学从事博士后科研工作，2015-2021年在北航物理学院工作，2021年调动至中国科学院理论物理研究所工作。主要研究领域是关联量子多体物理，发展了有限温度张量重正化群系列方法等。截止目前在包括Nature Commun., PRX, PRL等重要国际学术期刊上发表论文近60篇。

Reference: Nature Communications12, 4007 (2021).