title: Quantum transport of two-species Dirac fermions in dual-gated three-dimensional topological insulators.
abstract: Topological insulators are a novel class of quantum matter with a gapped insulating bulk, yet gapless spin-helical Dirac fermion conducting surface states. Here, we report local and non-local electrical and magneto transport measurements in dual-gated BiSbTeSe2 thin film topological insulator devices, with conduction dominated by the spatially separated top and bottom surfaces, each hosting a single species of Dirac fermions with independent gate control over the carrier type and density. We observe many intriguing quantum transport phenomena in such a fully tunable two-species topological Dirac gas, including a zero-magnetic-field minimum conductivity close to twice the conductance quantum at the double Dirac point, a series of ambipolar two-component half-integer Dirac quantum Hall states and an electron-hole total filling factor zero state (with a zero-Hall plateau), exhibiting dissipationless (chiral) and dissipative (non-chiral) edge conduction, respectively. Such a system paves the way to explore rich physics, ranging from topological magnetoelectric effects to exciton condensation.
authors.affiliation: Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA.|Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Ireneusz
authors.initials: I
authors.lastname: Miotkowski
authors.affiliation: Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA.|Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA.|School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Yong P
authors.initials: YP
authors.lastname: Chen