Related papers: Quantum Rings in Magnetic Fields and Spin Current …
Quantum rings connected to ballistic circuits couple strongly to external magnetic fields if the connection is not symmetric. By analytical theory and computer simulation I show that properly connected rings can be used to pump currents in…
We show that a tight-binding model device consisting of a laterally connected ring at half filling in a tangent time-dependent magnetic field can in principle be designed to pump a purely spin current. The process exploits the spin-orbit…
We investigate spin and charge current through a quantum dot pumped by a time-varying magnetic field. Using the density matrix method, quantum rate equations for the electronic occupation numbers in the quantum dot are obtained and solved…
We study the quantum spin pumping of an antiferromagnetic spin-1/2 chain with competing exchange interactions. We show that spatially periodic potential modulated in space and time acts as a quantum spin pump. In our model system, an…
We investigate two schemes for pumping spin adiabatically from a ferromagnet through an interacting quantum dot into a normal lead, which exploit the possibility to vary in time the ferromagnet's magnetization, either its amplitude or its…
We study charge and spin pumping in an interacting one-dimensional wire. We show that a spatially periodic potential modulated in space and time acts as a quantum pump inducing a dc-current component at zero bias. The current generated by…
An unpolarized charge current passing through a chaotic quantum dot with spin-orbit coupling can produce a spin polarized exit current without magnetic fields or ferromagnets. We use random matrix theory to estimate the typical spin…
We theoretically examine generation of spin-polarized current using multi-terminated quantum dot with spin-orbit interaction. First, a two-level quantum dot is analyzed as a minimal model, which is connected to $N$ ($\ge 2$) external leads…
Converting magnetization spin to orbital current often relies on strong spin-orbit interaction that may cause additional angular momentum dissipation. We report that coherent magnetization dynamics in magnetic nanostructures can…
We demonstrate that the combined effect of a spatially periodic potential, lateral confinement and spin-orbit interaction gives rise to a quantum ratchet mechanism for spin-polarized currents in two-dimensional coherent conductors. Upon…
We investigate parametric pumping of a spin-polarized current through a nearly-closed quantum dot in a perpendicular magnetic field. Pumping is achieved by tuning the tunnel couplings to the left and right lead - thereby operating the…
We propose schemes for generating spin currents into a semiconductor by adiabatic or non-adiabatic pumping of electrons through interacting quantum dots. The appeal of such schemes lies in the possibility to tune the pumping characteristics…
Quantum interference effects in rings provide suitable means for controlling spin at mesoscopic scales. Here we apply such a control mechanism to the spin-dependent transport in a ballistic quasi one dimensional ring patterned in two…
We investigate persistent charge and spin currents in a magnetic quantum ring threaded by an Aharonov-Bohm flux, in the presence of a side-coupled one-dimensional non-magnetic chain. The neighboring magnetic moments in the ring are arranged…
Spin and charge currents can be generated by an ac voltage through a one-channel quantum wire with strong electron interactions in a static uniform magnetic field. In a certain range of low voltages, the spin current can grow as a negative…
We study ballistic transport through semiconductor quantum point contact systems under different confinement geometries and applied fields. In particular, we investigate how the {\em lateral} spin-orbit coupling, introduced by asymmetric…
We report a theoretical study of the quantized spin pump in a traditional two-parameter quantum pump device that is based on the helical edge states of a quantum spin Hall insulator. By introducing two time-dependent magnetizations out of…
Pure spin currents are shown to be generated by an electrically controlled quantum pump applied at the edges of a topological insulator. The electric rather than the more conventional magnetic control offers several advantages and avoids,…
We theoretically propose quantum spin pumping mediated by magnons, under a time-dependent transverse magnetic field, at the interface between a ferromagnetic insulator and a non-magnetic metal. The generation of a spin current under a…
We propose a device acting as a spin valve which is based on a double quantum dot structure with parallel topology. Using the exact analytical solution for the noninteracting case we argue that, at a certain constellation of system…