title: Separation of top and bottom surface conduction in Bi2Te3 thin films.
abstract: Quantum spin Hall (QSH) systems are insulating in the bulk with gapless edges or surfaces that are topologically protected and immune to nonmagnetic impurities or geometric perturbations. Although the QSH effect has been realized in the HgTe/CdTe system, it has not been accomplished in normal 3D topological insulators. In this work, we demonstrate a separation of two surface conductions (top/bottom) in epitaxially grown Bi(2)Te(3) thin films through gate dependent Shubnikov-de Haas (SdH) oscillations. By sweeping the gate voltage, only the Fermi level of the top surface is tuned while that of the bottom surface remains unchanged due to strong electric field screening effects arising from the high dielectric constant of Bi(2)Te(3). In addition, the bulk conduction can be modulated from n- to p-type with a varying gate bias. Our results on the surface control hence pave a way for the realization of QSH effect in topological insulators which requires a selective control of spin transports on the top/bottom surfaces.
authors.affiliation: Device Research Laboratory, Department of Electrical Engineering, University of California, Los Angeles, CA 90095, USA.
authors.forename: Xinxin
authors.initials: X
authors.lastname: Yu
authors.forename: Liang
authors.initials: L
authors.lastname: He
authors.forename: Murong
authors.initials: M
authors.lastname: Lang
authors.forename: Wanjun
authors.initials: W
authors.lastname: Jiang
authors.forename: Faxian
authors.initials: F
authors.lastname: Xiu
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Liao
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Xufeng
authors.initials: X
authors.lastname: Kou
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Jianshi
authors.initials: J
authors.lastname: Tang
authors.forename: Guan
authors.initials: G
authors.lastname: Huang
authors.forename: Jin
authors.initials: J
authors.lastname: Zou
authors.forename: Kang L
authors.initials: KL
authors.lastname: Wang