title: Manipulating surface states in topological insulator nanoribbons.
abstract: Topological insulators display unique properties, such as the quantum spin Hall effect, because time-reversal symmetry allows charges and spins to propagate along the edge or surface of the topological insulator without scattering. However, the direct manipulation of these edge/surface states is difficult because they are significantly outnumbered by bulk carriers. Here, we report experimental evidence for the modulation of these surface states by using a gate voltage to control quantum oscillations in Bi(2)Te(3) nanoribbons. Surface conduction can be significantly enhanced by the gate voltage, with the mobility and Fermi velocity reaching values as high as ~5,800 cm(2) V(-1) s(-1) and ~3.7 × 10(5) m s(-1), respectively, with up to ~51% of the total conductance being due to the surface states. We also report the first observation of h/2e periodic oscillations, suggesting the presence of time-reversed paths with the same relative zero phase at the interference point. The high surface conduction and ability to manipulate the surface states demonstrated here could lead to new applications in nanoelectronics and spintronics.
authors.affiliation: Department of Electrical Engineering, University of California-Los Angeles, CA 90095, USA. xiu@ee.ucla.edu
authors.forename: Faxian
authors.initials: F
authors.lastname: Xiu
authors.forename: Liang
authors.initials: L
authors.lastname: He
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Lina
authors.initials: L
authors.lastname: Cheng
authors.forename: Li-Te
authors.initials: LT
authors.lastname: Chang
authors.forename: Murong
authors.initials: M
authors.lastname: Lang
authors.forename: Guan
authors.initials: G
authors.lastname: Huang
authors.forename: Xufeng
authors.initials: X
authors.lastname: Kou
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhou
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Jiang
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Chen
authors.forename: Jin
authors.initials: J
authors.lastname: Zou
authors.forename: Alexandros
authors.initials: A
authors.lastname: Shailos
authors.forename: Kang L
authors.initials: KL
authors.lastname: Wang