title: Electrically tuned magnetic order and magnetoresistance in a topological insulator.
abstract: The interplay between topological protection and broken time reversal symmetry in topological insulators may lead to highly unconventional magnetoresistance behaviour that can find unique applications in magnetic sensing and data storage. However, the magnetoresistance of topological insulators with spontaneously broken time reversal symmetry is still poorly understood. In this work, we investigate the transport properties of a ferromagnetic topological insulator thin film fabricated into a field effect transistor device. We observe a complex evolution of gate-tuned magnetoresistance, which is positive when the Fermi level lies close to the Dirac point but becomes negative at higher energies. This trend is opposite to that expected from the Berry phase picture, but is intimately correlated with the gate-tuned magnetic order. The underlying physics is the competition between the topology-induced weak antilocalization and magnetism-induced negative magnetoresistance. The simultaneous electrical control of magnetic order and magnetoresistance facilitates future topological insulator based spintronic devices.
authors.affiliation: 1] Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing 100084, P. R. China [2].
authors.forename: Zuocheng
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: 1] Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing 100084, P. R. China [2] Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China [3].
authors.forename: Xiao
authors.initials: X
authors.lastname: Feng
authors.affiliation: Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing 100084, P. R. China.
authors.forename: Minghua
authors.initials: M
authors.lastname: Guo
authors.affiliation: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China.
authors.forename: Kang
authors.initials: K
authors.lastname: Li
authors.affiliation: Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing 100084, P. R. China.
authors.forename: Jinsong
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China.
authors.forename: Yunbo
authors.initials: Y
authors.lastname: Ou
authors.affiliation: Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing 100084, P. R. China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Feng
authors.affiliation: 1] Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing 100084, P. R. China [2] Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China [3] Collaborative Innovation Center of Quantum Matter, Beijing 100084, P. R. China.
authors.forename: Lili
authors.initials: L
authors.lastname: Wang
authors.affiliation: 1] Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing 100084, P. R. China [2] Collaborative Innovation Center of Quantum Matter, Beijing 100084, P. R. China.
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.affiliation: 1] Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing 100084, P. R. China [2] Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China [3] Collaborative Innovation Center of Quantum Matter, Beijing 100084, P. R. China.
authors.forename: Ke
authors.initials: K
authors.lastname: He
authors.affiliation: 1] Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing 100084, P. R. China [2] Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China [3] Collaborative Innovation Center of Quantum Matter, Beijing 100084, P. R. China.
authors.forename: Xucun
authors.initials: X
authors.lastname: Ma
authors.affiliation: 1] Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing 100084, P. R. China [2] Collaborative Innovation Center of Quantum Matter, Beijing 100084, P. R. China.
authors.forename: Qikun
authors.initials: Q
authors.lastname: Xue
authors.affiliation: 1] Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing 100084, P. R. China [2] Collaborative Innovation Center of Quantum Matter, Beijing 100084, P. R. China.
authors.forename: Yayu
authors.initials: Y
authors.lastname: Wang