title: Zeeman effect on surface electron transport in topological insulator Bi2Se3 nanoribbons.
abstract: Topological insulators have exotic surface states that are massless Dirac fermions, manifesting special magnetotransport properties, such as the Aharonov-Bohm effect, Shubnikov-de Haas oscillations, and weak antilocalization effects. In the surface Dirac cone, the band structures are typically closely related to the p-orbitals and possess helical orbital texture. Here we report on the tunability of the transport properties via the interaction between the magnetic field and the spin-orbital angular momentum of the surface states in individual Bi2Se3 nanoribbons. Because the surface states have a large Landé factor and helical spin-orbital texture, the in-plane magnetic field induced Zeeman energy will result in the deformation of the Dirac cone, which gives rise to spin polarization of the surface states. The spin-dependent scattering of the conducting electrons on the existing local magnetic moments produces a giant negative magnetoresistance. The negative magnetoresistance is robust with a ratio of -20% at 2 K and -0.5% at 300 K under 14 T. The results are valuable for possible orbital-electronics based on topological insulators.
authors.affiliation: State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871, P. R. China. liaozm@pku.edu.cn.
authors.forename: Li-Xian
authors.initials: LX
authors.lastname: Wang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yan
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.forename: Zhi-Min
authors.initials: ZM
authors.lastname: Liao
authors.forename: Han-Chun
authors.initials: HC
authors.lastname: Wu
authors.forename: Da-Peng
authors.initials: DP
authors.lastname: Yu