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HL: Fachverband Halbleiterphysik
HL 13: Focus Session: Spin-Charge Interconversion (joint session MA/HL)
HL 13.6: Hauptvortrag
Montag, 16. März 2020, 17:45–18:15, HSZ 04
Nonlinear magnetoresistance from surface states of a topological insulator — •Giovanni Vignale1, Pan He2, Dapeng Zhu2, Shuyuan Shi2, Hyunsoo Yang2, Steven S.-L Zhang3,4, and Olle Heinonen3 — 1Department of Physics and Astronomy, University of Missouri-Columbia, Missouri 65211, USA — 21Department of Electrical and Computer Engineering, and NUSNNI, National University of Singapore, 117576, Singapore — 32Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA — 43Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA
Surface states of topological insulators exhibit the phenomenon of spin-momentum locking, whereby the orientation of an electron spin is determined by its momentum. We have discovered a close link between the spin texture of these states and a new type of nonlinear magnetoresistance, which depends on the relative orientation of the current with respect to the magnetic field as well as the crystallographic axes, and scales linearly with both the applied electric and magnetic fields. The nonlinear magnetoresistance originates from the conversion of a non-equilibrium spin current into a charge current under the application of an external magnetic field. Additionally, we find that the transverse component of the nonlinear resistance exhibits a pi/2 phase shift with respect to its longitudinal counterpart, in marked contrast to the usual pi/4 phase difference that exists between the linear planar Hall effect and the anisotropic magnetoresistance in typical topological insulators and transition metal ferromagnets.