Related papers: Coherent spin ratchets: A spin-orbit based quantum…
The concept of ratchets, driven asymmetric periodic structures giving rise to directed particle flow, has recently been generalized to a quantum ratchet mechanism for spin currents mediated through spin-orbit interaction. Here we consider…
We predict the possibility to generate a finite stationary spin current by applying an unbiased ac driving to a quasi-one-dimensional asymmetric periodic structure with Rashba spin-orbit interaction and strong dissipation. We show that…
We show that Rashba spin-orbit coupling may result in an energy gap in the spectrum of electrons in a two-mode quantum wire if a suitable confining potential is chosen. This leads to a dip in the conductance and a spike in the spin current…
We outline a generic ratchet mechanism for creating directed spin-polarized currents in ac-driven double well or double dot structures by employing resonant spin transfer through the system engineered by local external magnetic fields. We…
We investigate the existence of the pure spin ratchet effect in a dissipative quasi-one-dimensional system with Rashba spin-orbit interaction. The system is additionally placed into a transverse uniform stationary in-plane magnetic field.…
A net circulating current may appear within a quantum ring under finite bias. We study the characteristic features of the circular current in the presence of Rashba spin-orbit interaction (RSOI). Both charge and spin currents appear within…
We investigate the electron transport through a two-dimensional semiconductor with a nonuniform Rashba spin-orbit interaction. Due to the combination of the coherence effect and the Rashba interaction, a spontaneous spin-polarized current…
We study the response of a Bose-Einstein condensate to an unbiased periodic driving potential. By controlling the space and time symmetries of the driving we show how a directed current can be induced, producing a coherent quantum ratchet.…
Using response theory, we calculate the charge-current vortex generated by spin pumping at a point-like contact in a system with Rashba spin-orbit coupling. We discuss the spatial profile of the current density for finite temperature and…
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…
The influence of spin-orbit coupling in two-dimensional systems is investigated within the framework of the Landauer-Buettiker coherent scattering formalism. This formalism usually deals with spin-independent stationary states and,…
We demonstrate a spin pump to generate pure spin current of tunable intensity and polarization in the absence of charge current. The pumping functionality is achieved by means of an ac gate voltage that modulates the Rashba constant…
A scheme of spin diode is proposed that uses a step-like quantum wire with Rashba spin-orbit interaction, connected to two leads with different width. It is shown that a very large vertical spin-polarized current can be generated when…
We propose three different mechanisms for pumping spin-polarized currents in a ballistic circuit using a time-dependent magnetic field acting on an asymmetrically connected quantum ring at half filling. The first mechanism works thanks to a…
We investigate the possiblity of creating directed spin-polarized currents in a two-dimensional electron gas (2DEG) subject to an asymmetric magnetic field and an external adiabatic driving. We thereby generalize concepts of quantum charge…
We study the spin-dependent electronic transport through a one-dimensional ballistic quantum wire in the presence of Rashba spin-orbit interaction. In particular, we consider the effect of the spin-orbit interaction resulting from the…
Quantum interference effects in rings provide suitable means for controlling spin at mesoscopic scales. Here we apply such control mechanisms to coherent spin-dependent transport in one- and two-dimensional rings subject to Rashba…
Based on the Keldysh formalism, the Boltzmann kinetic equation and the drift diffusion equation have been derived for studying spin polarization flow and spin accumulation under effect of the time dependent Rashba spin-orbit interaction in…
We demonstrate that the tunnel oscillations of a biased double quantum dot can be employed as driving source for a quantum ratchet. As a model, we use two capacitively coupled double quantum dots. One double dot is voltage biased and…
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…