Spin and valley transports in junctions of Dirac fermions

Abstract

We study spin and valley transports in junctions composed of silicene and topological crystalline insulators. We consider normal/magnetic/normal Dirac metal junctions where a gate electrode is attached to the magnetic region. In normal/antiferromagnetic/normal silicene junction, we show that the current through this junction is valley and spin polarized due to the coupling between valley and spin degrees of freedom, and the valley and spin polarizations can be tuned by local application of a gate voltage. In particular, we find a fully valley and spin polarized current by applying the electric field. In normal/ferromagnetic/normal topological crystalline insulator junction with a strain induced in the ferromagnetic segment, we investigate valley resolved conductances and clarify how the valley polarization stemming from the strain and exchange field appears in this junction. It is found that changing the direction of the magnetization and the potential in the ferromagnetic region, one can control the dominant valley contribution out of four valley degrees of freedom. We also review spin transport in normal/ferromagnetic/normal graphene junctions, and spin and valley transports in normal/ferromagnetic/normal silicene junctions for comparison.

arXiv comment13 pages, 10 figures

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Cited by in corpus (5)

• Collective plasmonic excitations in double-layer silicene at finite temperature
• Spin helical states and spin transport of the line defect in silicene lattice
• Strain control of real-and lattice-spin currents in a silicene junction
• Lattice-pseudospin and spin-valley polarizations in dual ferromagnetic-gated silicene junction
• Valley detection using a graphene gradual pn junction with spin-orbit coupling: an analytical conductance calculation