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7003全讯入口“博约学术论坛”系列报告(第130期)

来源: 作者: 发布时间:2017-10-23

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时间: 2017-10-23

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题目:铁基超导和量子自旋阻挫材料的核磁共振研究

报告人:于伟强教授(中国人民大学物理系)

时间:2017年10月27日(周五)上午10:00

地点:7003全讯入口中心教学楼610

Abstract:

Strong electron correlations produce rich and novel quantum states. Nuclear magnetic resonance (NMR), utilizing the quantum spin and/or quadrupolar moments of nuclei, is a powerful local probe to detect the nature and the low-energy spin fluctuations of quantum states in strongly correlated electron systems.   

In this talk, I will focus on our recent high-pressure NMR studies on two classes of materials. In iron-based high-temperature superconductors, we found signatures of charge ordering [1], established intrinsic quantum magnetic structures [2], and revealed high-temperature short-range-ordered nematicity [3] in different compounds. For a spin-orbit coupled Mott insulator -RuCl3, which was proposed to have proximate Kitaev spin-liquid behaviors, we found that its magnetic structure can be suppressed either by magnetic field or by pressure, resulting in a gapless spin-liquid-like phase [4] and a valence-bond-solid-like phase [5] respectively. The existence of these novel quantum states reveals the interplays among spin, charge, orbital, and lattice degrees of freedom.

References: [1] P. S. Wang et al., PRB 93, 085129 (2016); [2] P. S. Wang et al., PRL 117, 237001 (2016); [3] P. S. Wang et al., PRB 96, 094528 (2017) (2017); [4] J. Zheng et al., arXiv: 1703.08474 (2017); [5] Y. Cui et al., arXiv:1706.02697 (2017).

简历:

于伟强,中国人民大学物理系教授。2004年获得UCLA博士学位,2004-2008年先后在马里兰大学、马克马斯特大学做博士后,2008年起任现职。2011年获得首届国家基金委优青资助。回国后搭建了低温固体核磁共振系统,并结合极低温和高压技术,专注于高温超导材料和量子磁性的物性研究,在铁基高温超导材料的超导对称性、向列序、自旋涨落和超导的关联,以及自旋阻挫材料的自旋液体态等方面做出前沿研究成果,其中在物理评论快报和物理评论X发表6篇学术论文。

联系方式:7003全讯入口办公室(68913163)

邀请人:杨帆教授网址:/