应物理科学与技术学院李志伟副教授邀请，德国马普学会固体化物所郭汉杰博士来我院访问并做学术报告，欢迎大家参加。

报告信息如下：

时间：2018年1月5日（星期五五）上午10：00

地点：格致楼3016学术报告厅

报告人：郭汉杰，主要从事凝聚态物理领域相关的研究工作，是晶体生长、晶体结构及XRD精修，磁结构分析、中子/X-射线散射及uSR等领域的专家。

报告题目：Magnetic Ground State of the Pyrochlore Iridate

摘要：

Pyrochlore iridates (R₂Ir₂O₇,R= Y and rare earth elements) are of great interest due to the interplay between the relatively large spin-orbit coupling and the electron-electron correlations which may induce novel phases such as topological Mott insulators, axion insulators and Weyl semimetals. One important task for understanding the properties of these compounds is the determination of the magnetic structure which is challenging due to the small moment of the Ir⁴⁺ions and strong neutron absorption from Ir atoms. In this talk, I will present our studies on the magnetic ground state of Nd₂Ir₂O₇and Tb₂Ir₂O₇by means of muon spin relaxation and powder neutron diffraction technique [1-3]. Our studies determine the magnetic structure directly, which can be described as the so-called all-in/all-out structure. The comparison between the Nd₂Ir₂O₇and Tb₂Ir₂O₇results also shows that the Ir⁴⁺moment is larger with higherT_N(smallerR-ionic radius as well), suggesting that the hybridization between the Ir 5dand O 2porbitals is smaller with decreasingR-ionic radius.

References:

[1] H. Guo, K. Matsuhira, I. Kawasaki, M. Wakeshima, Y. Hinatsu, I. Watanabe, and Z. Xu, Phys. Rev. B, 88, 060411 (R) (2013).

[2] H. Guo, C. Ritter and A. C. Komarek, Phys. Rev. B 94, 161102(R) (2016).

[3] H. Guo, C. Ritter and A. C. Komarek,Phys. Rev. B 96, 144415 (2017)

报告人简介：

2014/09 - now: Scientist at Max-Planck-Institute for Chemical Physics of Solids, Dresden Germany

2009/09 - 2014/06: PhD, Department of Physics, Zhejiang University, China

2012/02 - 2013/12: International Program Associate student in RIKEN, Japan

2005/09 - 2009/06: B.S., Department of Mechanical Engineering and Automation, Huaqiao University, China.