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RESEARCH PRODUCT
A topological current divider
Francesco Romeosubject
PhysicsCondensed Matter - Materials ScienceSpintronicsSpin polarizationCondensed Matter - Mesoscale and Nanoscale PhysicsMaterials Science (cond-mat.mtrl-sci)FOS: Physical sciences02 engineering and technology021001 nanoscience & nanotechnologyPolarization (waves)Topology01 natural sciencesHelicityCurrent dividerSymmetry (physics)Topological insulator0103 physical sciencesMesoscale and Nanoscale Physics (cond-mat.mes-hall)Condensed Matter::Strongly Correlated ElectronsCurrent (fluid)010306 general physics0210 nano-technologydescription
We study the transport properties of a hybrid junction made of a ferromagnetic lead in electrical connection with the helical edge modes of a two-dimensional topological insulator. In this system, the time reversal symmetry, which characterizes the ballistic edge modes of the topological insulator, is explicitly broken inside the ferromagnetic region. This conflict situation generates unusual transport phenomena at the interface which are the manifestation of the interplay between the spin polarization of the injected current and the spin-momentum locking mechanism operating inside the topological insulator. We show that the spin polarized current originated in the ferromagnetic region is asymmetrically divided in spatially separated branch currents sustained by edge channels with different helicity inside the topological insulator. The above findings provide the working principle of a topological current divider in which the relative intensity of the branch currents is determined by the polarization of the incoming current. We discuss the relevance of this effect in spintronics where, for instance, it offers an alternative way to measure the current polarization generated by a ferromagnetic electrode.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2020-11-23 |