Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 20: Spin controlled transport II

HL 20.2: Talk

Tuesday, March 28, 2006, 15:30–15:45, BEY 118

Spin Dynamics During Transport Via Dynamic Quantum Dots — •James AH Stotz, Rudolph Hey, Paulo V Santos, and Klaus H Ploog — Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany

Quantum information processing using electron spins in semiconductor structures requires the coherent transport and manipulation of spin polarized carriers. Previous studies have typically focussed on either the transport of spins with little control of their microscopic movement or the use of quantum dots to manipulate spins locally without microscopic transport. Recent work [1] using the unique system of dynamic quantum dots (DQDs) shows that electron spins can be transported over long distances and manipulated while retaining their microscopic confinement. The DQDs are produced by the superposition of piezoelectric potentials from surface acoustic waves propagating along orthogonal directions on a GaAs/(Al,Ga)As quantum well sample. While it is clear that the confinement potential of the DQDs reduces D’yakonov-Perel’ spin dephasing during transport, the effects of the strain and magnetic fields on spin dephasing are much more complicated. We will discuss the underlying mechanisms behind the ability to transport spins over long distances including the impact of confinement on spin coherence. In addition, the strong dephasing of the spin coherence in an external magnetic field will be addressed, and the influence of the acoustic strain field on the transport will be introduced.

[1] J.A.H. Stotz et al., Nature Materials 4, 585-588 (2005)

[2] Financial support from the BMBF Nanoquit project is appreciated.