Dresden 2009 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 29: Quantum dots: Optical properties II

HL 29.3: Vortrag

Mittwoch, 25. März 2009, 10:00–10:15, BEY 154

Phonon-assisted tunneling in two-electron quantum dot molecules — •Anna Grodecka¹, Paweł Machnikowski², and Jens Förstner¹ — ¹Computational Nanophotonics Group, Theoretical Physics, University Paderborn, Paderborn, Germany — ²Institute of Physics, Wrocław University of Technology, Wrocław, Poland

Spin states of two-electron doped quantum dot molecules (QDMs) have been employed in many quantum logical gates proposals where tunneling processes play a crucial role. Therefore, their timescales and efficiency are of primary importance. In this work, phonon-assisted tunneling in a lateral two-electron QDM is studied theoretically [1]. The phonon and Coulomb interactions are simultaneously incorporated. We take into account interaction with acoustic phonons via deformation potential and piezoelectric coupling and show that the latter can be even the dominant contribution. The phonon-assisted tunneling rates calculated for GaAs QDMs reach values (up to 160/ns) many orders of magnitude higher than the other decoherence processes resulting from spin-orbit or hyperfine interaction, thus can play a dominant role in QDM-based quantum gates.
1. A. Grodecka, P. Machnikowski, and J. Förstner, Phys. Rev. B 78, 085302 (2008).