Time: 10:00am (UTC/GMT+08:00, Beijing/Shanghai), Dec. 18 (Fri.), 2020

Venue: KITS Seminar Room, 4th floor, No. 7 Building, UCAS Zhong-Guan-Cun Campus [View on maps]

Speaker: Prof. Xing-Ye Lu  (BNU)

Abstract:

FeSe is a special material among the families of iron-based superconductors because of its extended nematic phase and highly-tunable anisotropic superconductivity. Upon cooling, FeSe enters a paramagnetic orthorhombic (nematic) state below Ts~90K with no static antiferromagnetic order formed. In this talk, I will present our RIXS and neutron scattering results on the magnetic excitations in the nematic state of uniaxial-strain detwinned FeSe, and discuss their connection to the origin of the high-Tc superconductivity in iron-based superconductors.

After that, I would like to present our recent progress on a quantum-spin-liquid (QSL) candidate—NaYbSe2. Compared with previous QSL candidates hosting substantial structural and/or exchange-interaction disorder, triangular-lattice antiferromagnetic system NaYbSe2 is a better candidate for the realization of QSL physics.  We use various experimental techniques including heat capacity, magnetic susceptibility, elastic and inelastic neutron scattering to show the ground state of NaYbSe2 is likely a spinon Fermi surface QSL with gapless deconfined excitations. 

报告人简介：

鲁兴业，北京师范大学物理学系副研究员、博士生导师，2019年国家优秀青年科学基金获得者。2014年博士毕业于中国科学院物理研究所；毕业论文获得中国科学院优秀博士论文奖；2014年11月至2016年12月在美国莱斯大学和瑞士保罗谢勒研究所瑞士光源从事博士后研究，入选玛丽居里基金会资助的PSI Fellow(2015-2017)。 2017年回国后到北京师范大学物理学系开展工作。主要研究方向为关联电子材料的中子散射和共振非弹性x射线散射（RIXS）研究，关注的体系包括铁基超导、铜基超导、铱氧化物、低维量子磁性材料等等 。已在Science、Nature子刊、PRL等学术期刊发表论文80余篇，总引用次数1900余次。

Invited by Prof. Long Zhang