title: Ultra-low carrier concentration and surface-dominant transport in antimony-doped Bi₂Se₃ topological insulator nanoribbons.
abstract: A topological insulator is the state of quantum matter possessing gapless spin-locking surface states across the bulk band gap, which has created new opportunities from novel electronics to energy conversion. However, the large concentration of bulk residual carriers has been a major challenge for revealing the property of the topological surface state by electron transport measurements. Here we report the surface-state-dominant transport in antimony-doped, zinc oxide-encapsulated Bi(2)Se(3) nanoribbons with suppressed bulk electron concentration. In the nanoribbon with sub-10-nm thickness protected by a zinc oxide layer, we position the Fermi levels of the top and bottom surfaces near the Dirac point by electrostatic gating, achieving extremely low two-dimensional carrier concentration of 2×10(11) cm(-2). The zinc oxide-capped, antimony-doped Bi(2)Se(3) nanostructures provide an attractive materials platform to study fundamental physics in topological insulators, as well as future applications.
authors.affiliation: Department of Applied Physics, Stanford University, 476 Lomita Mall, McCullough 343, Stanford, California 94305, USA.
authors.forename: Seung Sae
authors.initials: SS
authors.lastname: Hong
authors.forename: Judy J
authors.initials: JJ
authors.lastname: Cha
authors.forename: Desheng
authors.initials: D
authors.lastname: Kong
authors.forename: Yi
authors.initials: Y
authors.lastname: Cui