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25日(周三)上午10:00
地点：北京理工大学中心教学楼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：物理学院办公室（68913163）
 

邀请人：杨帆教授
网址：http://physics.bit.edu.cn/