منابع مشابه
Resonant tunneling-based spin ratchets
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 show its applicability to semiconductor nanostructures by considering coherent transport through two coupled lateral quantum dots, where the energy levels of ...
متن کاملCoherent Spin Ratchets
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 adiabatic ac-driving, in the absence of a net static bias, the system generates a directed spin current while the total charge current is zero. We analyze the u...
متن کاملSpin-Orbit Based Coherent Spin Ratchets
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 such systems in the coherent mesoscopic regime and generalize the proposal of a minimal spin ratchet model based on a non-interacting clean quantum wire with ...
متن کاملQuantum dissipative Rashba spin ratchets.
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 under a finite coupling strength between the orbital degrees of freedom the electron dynamics at low temperatures exhibits a pure spin ratchet behavior, i.e., a ...
متن کاملZeeman ratchets: Rectification of spin current via magnetic fields
We investigate the possibility of creating directed spin-polarized currents in a two-dimensional electron gas (2DEG) subject to an inhomogeneous magnetic field and an external adiabatic driving. We thereby generalize concepts of quantum charge ratchets to the case with spin. Due to the Zeeman term in the Hamiltonian, spin-up and -down electrons experience different effective potentials, which c...
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ژورنال
عنوان ژورنال: EPL (Europhysics Letters)
سال: 2009
ISSN: 0295-5075,1286-4854
DOI: 10.1209/0295-5075/87/17001