Seminar: Sihan Zhao

Title: Electronic interactions and Luttingerphysics in carbon nanotubes& two-dimensional NbS₂ layered materials

Speaker: Dr.Sihan Zhao, University of California, Berkeley

Place: Room 423, Building 12, Yuquan Campus

Time: 10:00-11:30am, July 9th (Monday)

Abstract

For the past few decades, materials with low dimensions have attracted researcherstremendous interests, which leads to the discoveries of novel physics and chemistry with extraordinary properties. One-dimensional (1D) carbon nanotubes (CNTs), two-dimensional (2D) graphene, and more recently, 2D transition metal dichalcogenides (TMDs), three well-known representatives of nanomaterials, have provided unprecedented playgrounds to explore fundamental physics in condensed mattersand have pioneered a lot of promising applications of nanomaterials in electronics, optics and energies [1,2].  In this talk, I’ll first discuss our experimental findings of electronic coupling in structure-defined double-wall carbon nanotubes (DWNTs) with combinations of transmission electron microscope (TEM) and optical Rayleigh scattering spectroscopy[3]. Then I’ll talk about our work on the first definitive test of Luttingerliquid physics (a new paradigm of interacting fermions in 1D system) in carbon nanotubes. This is achieved by correlating electron tunneling and plasmon propagation in a well-defined Luttinger liquid, which is probed by low-temperature electrical transport and optical near-fieldnanoscopy [4]. I’ll talk about the synthesis, structural identifications, and transport properties of a 2D metallic TMD, i.e. NbS₂ [5]. If time allows, I’ll also talk about our achievement on optical absorption measurement of bottom-up atomic-precise graphene nanoribbons (GNRs) on insulating substrates by using light polarization control [6]. 

References

[1]A. K.Geim,Novoselov, K. S. Novoselov.Nat. Mater. 6, 183-191 (2007).

[2] Q. H. Wang, K. Kalantar-Zadeh; A. Kis, J. N. Coleman, M. S. Strano. Nat. Nanotech.7,699-712 (2012).

[3] S. Zhao, T. Kitagawa, Y. Miyauchi, K. Matsuda, H. Shinohara, R. Kitaura. Nano Research 7, 1548  (2014)  

[4] S. Zhao, S. Wang, F. Wu, W. Shi, I. Q. Utama, T. Lyu, L. Jiang, Y. Su, S. Wang, K. Watanabe, T. Taniguchi, A. Zettl, X. Zhang, C. Zhou, F. Wang. Phys. Rev. Lett. Accepted (2018)

[5] S. Zhao, T. Hotta, T. Koretsune, K. Watanabe, T. Taniguchi, K. Sugawara, T. Takahashi, H. Shinohara, R. Kitaura. 2D Materials3 (2), 025027 (2016)  

[6] S. Zhao, G. Barin, T. Lyu, T. Cao, R. Fasel, F. Wang. In preparation (2018) 

About the Speaker

Sihan Zhao（赵思瀚） received his Bachelor degree (major: Materials Science) in 2010 from Jilin University. He received his PhD degree (Science) in early 2016 from Nagoya University, Japan. After that he has become a postdoctoral researcher in the Department of Physics, University of California, Berkeley under the guidance of Prof. Feng Wang. His current research topics include:Luttinger liquid physics in 1D carbon nanotubes and optical properties of graphene nanoribbons. Awards: (1) Japan Society for the Promotion of Science Research Fellow(2013-2016); (2) Young Scientist Poster Award in the 45th Fullerenes-Nanotubes-Graphene General Symposium (Aug. 2013);(3) Annual Research Award in IGER Annual meeting 2014 (Nagoya University, Jan. 2015).