題目：鐵基超導(dǎo)和量子自旋阻挫材料的核磁共振研究
報(bào)告人：于偉強(qiáng)教授（中國(guó)人民大學(xué)物理系）
時(shí)間：2017年10月25日(周三)上午10:00
地點(diǎn)：北京理工大學(xué)中心教學(xué)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(jiǎn)歷：
于偉強(qiáng),，中國(guó)人民大學(xué)物理系教授。2004年獲得UCLA博士學(xué)位,，2004-2008年先后在馬里蘭大學(xué),、馬克馬斯特大學(xué)做博士后，2008年起任現(xiàn)職,。2011年獲得首屆國(guó)家基金委優(yōu)青資助,。
回國(guó)后搭建了低溫固體核磁共振系統(tǒng)，并結(jié)合極低溫和高壓技術(shù),，專(zhuān)注于高溫超導(dǎo)材料和量子磁性的物性研究,，在鐵基高溫超導(dǎo)材料的超導(dǎo)對(duì)稱(chēng)性,、向列序、自旋漲落和超導(dǎo)的關(guān)聯(lián),，以及自旋阻挫材料的自旋液體態(tài)等方面做出前沿研究成果,，其中在物理評(píng)論快報(bào)和物理評(píng)論X發(fā)表6篇學(xué)術(shù)論文。
聯(lián)系方式：物理學(xué)院辦公室（68913163）
 

邀請(qǐng)人：楊帆教授
網(wǎng)址：http://physics.bit.edu.cn/