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HL: Halbleiterphysik

HL 9: Poster I

HL 9.72: Poster

Montag, 27. März 2006, 15:15–17:45, P3

Cotunneling through quantum dots with phonon-assisted spin-flip processes — •Jörg Lehmann and Daniel Loss — Departement für Physik und Astronomie, Universität Basel, CH-4056 Basel, Switzerland

For applications in spintronics and quantum computing a detailed knowledge about relaxation and coherence properties of the considered systems is crucial. Here, we investigate to what extent measurements of the cotunneling current through semiconductor quantum dots can provide information about a major source of decoherence in these systems, namely spin-flip processes induced by the coupling to acoustic phonons of the environment. An expression for the phonon-assisted cotunneling current is derived by means of a generalised Schrieffer-Wolff transformation, which allows one to eliminate to lowest order the dot-lead coupling. Explicit expressions for the elastic and inelastic contributions to the cotunneling current are given and the influence of the spin-phonon coupling on the heating of the dot is considered. The general results are evaluated for the case of a parabolic semiconductor quantum dot with Rashba and Dresselhaus spin-orbit coupling and a method for the determination of the spin-phonon relaxation rate is proposed. [1]

[1] J. Lehmann and D. Loss, arXiv:cond-mat/0509420.