学术报告 Probe Physics in Nano-scale by Scanning Tunneling Microscopy
【报告题目】 Probe Physics in Nano-scale by Scanning Tunneling Microscopy
【报 告 人】 Prof. Shuai-Hua Ji
Department of Physics, Tsinghua University
【时 间】 2017-05-31 星期三 16:00
【地 点】 理工楼801
Scanning tunneling microscope (STM), combining with extreme conditions, such as ultra-low temperature and high magnetic field, has been one of main tools to explore frontiers of condensed matter physics. High spatial resolution make it as an idea platform to probe the physics in nano-scale, which usually cannot be accessed by the macroscopic measurement. In this talk, I’ll give a few examples to demonstrate the capabilities of STM. (1) We studied the bound states of superconducting gap induced by the single magnetic atoms. Our high energy resolution (better than 0.1 meV) spectra reveal multi-bound-states in superconducting gap for the first time in the atomic scale. The bound states of dimmer could even probe the magnetic exchange interaction between magnetic atoms . (2) We show that the ferroelectric state of ultra-thin SnTe film can be studied by STM. Unexpected polarization enhancement has been revealed in atomic thick SnTe film . (3) Multi-probe STM could study transport properties at the atomic scales. It has been successfully used in investigating local transport of epitaxial graphene. The spatial resolved potential distribution shows the electronic scattering at the atomic steps and monolayer-bilayer boundaries .
1. S. H. Ji, T. Zhang, Y. S. Fu, X. Chen, X. C. Ma, J. Li, W. H. Duan, J. F. Jia, Q. K. Xue. “High-resolution scanning tunneling spectroscopy of magnetic-impurity-induced bound states in the superconducting gap of Pb thin-films” Phys. Rev. Lett. 100, 226801(2008).
2. Kai Chang, Junwei Liu, Haicheng Lin, Na Wang, Kun Zhao, Anmin Zhang, Feng Jin,Yong Zhong, Xiaopeng Hu, Wenhui Duan, Qingming Zhang, Liang Fu, Qi-Kun Xue, Xi Chen, Shuai-Hua Ji “Discovery of robust in-plane ferroelectricity in atomic-thick SnTe” Science 353, 274 (2016).
3. S. H. Ji, J. B. Hannon，R. M. Tromp, V. Perebeinos, J. Tersoff, F. M. Ross, “Atomic scale transport in epitaxial graphene” Nat. Mater. 11, 114(2012).
Shuai-Hua Ji is an associate professor in Department of Physics of Tsinghua University. He received his Ph.D. degree in Institute of Physics, Chinese Academy of Science in 2008. He joined IBM T. J. Watson Research Center as a postdoctoral fellow in 2008. In 2012, he joined the faculty at Tsinghua University. His main research area is the quantum phenomenon in the low dimensional system. He is interested in the superconductivity, collective phenomena, topological related states and correlated electronic states in the low dimensional system. He received IBM Materials Research Community Best paper award in 2012, National Natural Science Outstanding Youth Foundation in 2016, Young scholars of Cheung Kong Scholars Award in 2016.
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