报告专家：刘荧
报告时间：2019年6月5日10：00
报告地点：行健楼437

摘要：Much of the work on Sr2RuO4 has been focused on its pairing symmetry, motivated originally by a theoretical prediction that this low-temperature superconductor is an odd-parity, spin-triplet superconductor. Many experimental and theoretical results concerning this issue have been obtained in the intervening years. Nevertheless, the precise pairing state realized in Sr2RuO4 is yet to be resolved. Our work has focused on the transport and tunneling measurements on Sr2RuO4, in particular, the Josephson effect and related phase-sensitive measurements detecting the symmetry of the orbital part of the Cooper pair wave function. In this talk I will present some details of our earlier phase-sensitive measurements on bulk Sr2RuO4 in view of recently reinvigorated interest in the pairing symmetry issue. I will also discuss our more recent work on doubly connected mesoscopic cylinders of Sr2RuO4 prepared by a combination of conventional and unconventional nanofabrication techniques. Our work was aimed at detecting evidence for the half-flux-quantum state using a different set of measurements and clarifying the effect of the in-plane magnetic field that was shown to be necessary to yield the half-height-step feature seen in the magnetometry measurements. I will present data on magnetoresistance oscillations of our cylinders in the presence of an in-plane magnetic field and discuss the implications of our results.

报告人简介：Ying Liu, professor of physics at Pennsylvania State University and Hongwen Professor of Physics at Shanghai Jiao Tong University (part-time), received his BS degree from Peking University in 1982. He earned a MS degree, under the direction of Professor Zhao-Qing Zhang at Institute of Physics, Chinese Academy of Sciences, Beijing in 1984. Prof. Liu did his Ph. D. thesis research under the direction of Professor Allen M. Goldman at University of Minnesota, and received his Ph.D. degree in 1991. After three-year postdoctoral research at University of Colorado, Boulder, Prof. Liu joined the faculty of Department of Physics of the Pennsylvania State University in 1994, becoming tenured full professor in 2005. His research has focused on the study of low-dimensional and unconventional superconductors, in particular, odd-parity, spin-triplet superconductor Sr2RuO4. He also worked on graphene, topological insulators, 2D crystals of transition metal oxides and chalcogenides, as well as strongly correlated electronic systems. Professor Liu received an NSF Career Award in 1997 and was selected as a fellow of the American Physical Society in 2006. He was awarded an Outstanding Young Investigator (Type B) award from National Science Foundation of China and a Chang Jiang Lecturer Professorship from Chinese Ministry of Education.