Topic: Topological Insulators from Bottom up

Speaker: Dr. Xuan Gao

          Case Western Reserve University, U.S.A.

Abstract：

Topological insulators (TIs) are novel quantum materials with conducting gapless surface states (SS) and insulating bulk. Nanostructures with large surface-to-volume ratio are thus attractive for the studies of topological SS in TI materials, which, unfortunately often have high residual conductivity in the bulk due to defects. In this talk, we will discuss the chemical synthesis and electron transport studies of various nanostructures (nanowires, ribbons, plates, sheets) of chalcogenide family of TIs (Bi₂Se₃, Bi₂Te₃ etc). In particular, we highlight the successful control of Fermi level to the Dirac point of SS by gating, TI to trivial insulator transition induced by doping, as well as the observation and investigation of a novel linear magneto-resistance effect.

Biography:

Prof. Gao was born in JiangXi province. He received his B.S. degree in Applied Physics from South China University of Technology in 1998. In 2003, he received his Ph.D. degree at Columbia University. His Ph.D. thesis was awarded the Robert Simon Memorial Prize for the most outstanding thesis by the Dept of Applied Physics and Applied Math of Columbia University. Between 2003 and 2007, he was postdoc first with Dr. Greg Boebinger at Los Alamos National Lab then Prof. Charles Lieber at Harvard University. In 2007, he joined Case Western Reserve University as a faculty member. He is currently an associate professor. Prof. Gao’s research areas include transport and many body physics in low dimensional electron systems; the rational synthesis, fundamental understanding and functional engineering of nanoscale materials and devices. His achievement was recognized by multiple awards such as the CAREER Award of National Science Foundation of the USA, the 2012 Outstanding Young Researcher Award of the International Organization of Chinese Physicists and Astronomers.