Spin-flip scattering in time-dependent transport through a quantum dot: Enhanced spin-current and inverse tunneling magnetoresistance
arXiv:0806.4480 · doi:10.1103/PhysRevB.78.155301
Abstract
We study the effects of spin-flip scatterings on the time-dependent transport properties through a magnetic quantum dot attached to normal and ferromagnetic leads. The transient spin-dynamics as well as the steady-state tunneling magnetoresistance (TMR) of the system are investigated. The absence of a definite spin quantization axis requires the time-propagation of two-component spinors. We present numerical results in which the electrodes are treated both as one-dimensional tight-binding wires and in the wide-band limit approximation. In the latter case we derive a transparent analytic formula for the spin-resolved current, and transient oscillations damped over different time-scales are identified. We also find a novel regime for the TMR inversion. For any given strength of the spin-flip coupling the TMR becomes negative provided the ferromagnetic polarization is larger than some critical value. Finally we show how the full knowledge of the transient response allows for enhancing the spin-current by properly tuning the period of a pulsed bias.
11 pages, 13 eps figures
References in corpus (5)
- Single-shot read-out of an individual electron spin in a quantum dot
- A time-dependent approach to electron pumping in open quantum systems
- Approach to steady state transport in nanoscale conductors
- Bound states in ab initio approaches to quantum transport: A time-dependent formulation
- Spin-Dependent Ringing and Beats in a Quantum Dot System