Speaker: Branislav Nikolic, University of Delaware
Abstract: I review recent studies of the shot noise of spin-polarized charge currents and pure spin currents in multiterminal semiconductor nanostructures with spin-orbit couplings or zigzag graphene nanoribbons attached to metallic electrodes. Akin to early utilization of noise in mesoscopic devices, where random time-dependent current fluctuations contain much more information about the transport than revealed through average current and conductance, spin-dependent shot noise emerges as a rich electrical tool to probe spin as magnetic degree of freedom. The Fano factor (noise-to-current ratio) of such noise can quantify decoherence of transported spins, or reveal the origin of the spin Hall effect (SHE) in simply-connected devices and probe interference effects in SHE induction in multiply-connected Aharonov-Casher rings. Finally, while the conventional spin-degenerate shot noise has very recently become important experimental tool to study ballistic transport through evanescent modes in graphene samples attached to metallic electrodes, in ribbons with zigzag edges which favor edge magnetic ordering when Coulomb interaction is "turned on", modification of the shot noise can be exploited to detect this unusual form of low-dimensional carbon-based magnetism.