title: Manipulating surface-related ferromagnetism in modulation-doped topological insulators.
abstract: A new class of devices based on topological insulators (TI) can be achieved by the direct engineering of the time-reversal-symmetry (TRS) protected surface states. In the meantime, a variety of interesting phenomena are also expected when additional ferromagnetism is introduced to the original topological order. In this Letter, we report the magnetic responses from the magnetically modulation-doped (Bi(z)Sb(1-z))2Te3/Cr(x)(Bi(y)Sb(1-y))2Te3 bilayer films. By electrically tuning the Fermi level across the Dirac point, we show that the top TI surface carriers can effectively mediate the magnetic impurities and generate robust ferromagnetic order. More importantly, such surface magneto-electric effects can be either enhanced or suppressed, depending on the magnetic interaction range inside the TI heterostructures. The manipulation of surface-related ferromagnetism realized in our modulation-doped TI device is important for the realization of TRS-breaking topological physics, and it may also lead to new applications of TI-based multifunctional heterostructures.
authors.affiliation: Device Research Laboratory, Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States.
authors.forename: Xufeng
authors.initials: X
authors.lastname: Kou
authors.forename: Liang
authors.initials: L
authors.lastname: He
authors.forename: Murong
authors.initials: M
authors.lastname: Lang
authors.forename: Yabin
authors.initials: Y
authors.lastname: Fan
authors.forename: Kin
authors.initials: K
authors.lastname: Wong
authors.forename: Ying
authors.initials: Y
authors.lastname: Jiang
authors.forename: Tianxiao
authors.initials: T
authors.lastname: Nie
authors.forename: Wanjun
authors.initials: W
authors.lastname: Jiang
authors.forename: Pramey
authors.initials: P
authors.lastname: Upadhyaya
authors.forename: Zhikun
authors.initials: Z
authors.lastname: Xing
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Faxian
authors.initials: F
authors.lastname: Xiu
authors.forename: Robert N
authors.initials: RN
authors.lastname: Schwartz
authors.forename: Kang L
authors.initials: KL
authors.lastname: Wang
mesh_terms: D001729:Bismuth / Q000737:chemistry*; D003460:Crystallization; D006801:Humans; D059346:Magnets; D049329:Nanostructures / Q000737:chemistry*; D012643:Selenium / Q000737:chemistry; D013499:Surface Properties; D013691:Tellurium / Q000737:chemistry
chemical_list: D012643:Selenium; D013691:Tellurium; D001729:Bismuth