題目：鐵基超導和量子自旋阻挫材料的核磁共振研究
報告人：于偉強教授（中國人民大學物理系）
時間：2017年10月25日(周三)上午10:00
地點：北京理工大學中心教學樓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).
 

簡歷：
于偉強，中國人民大學物理系教授。2004年獲得UCLA博士學位，2004-2008年先后在馬里蘭大學、馬克馬斯特大學做博士后，2008年起任現職。2011年獲得首屆國家基金委優青資助。
回國后搭建了低溫固體核磁共振系統，并結合極低溫和高壓技術，專注于高溫超導材料和量子磁性的物性研究，在鐵基高溫超導材料的超導對稱性、向列序、自旋漲落和超導的關聯，以及自旋阻挫材料的自旋液體態等方面做出前沿研究成果，其中在物理評論快報和物理評論X發表6篇學術論文。
聯系方式：物理學院辦公室（68913163）
 

邀請人：楊帆教授
網址：http://physics.bit.edu.cn/