Regensburg 2004 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 44: Poster II
HL 44.30: Poster
Donnerstag, 11. März 2004, 16:30–19:00, Poster A
Strong magneto-resistance in double quantum dots due to charge polarization — •Bernhard Wunsch1, David Jacob2, and Daniela Pfannkuche1 — 1I. Institute of Theoretical Physics, University of Hamburg, Jungiusstr. 9, D–20355 Hamburg, Germany — 2Department of Applied Physics, University of Alicante, Cra San Vicente, 03690 San Vicente del Raspeig (Alicante), Spain
We report on magnetic field induced ground state crossings for vertically coupled double quantum dots between states with same angular momentum and spin but different isospin parity. In contrast to the well known crossings between states of different angular momentum [1] a crossing between states that differ only in parity can lead to a vertical charge polarization.
We show that the polarization of the three electron ground state can be detected in a transport experiment through the double quantum dot[2]. At the magnetic field, where originally the crossing occurred, we find a strong suppression of the Coulomb peak associated with a transition between two and three electrons in the double dot, due to the polarization of the three electron ground state. Finally we want to point out, that for a low electric field the mixing of the crossing states is very sensitive to the magnetic field, which may prove to be useful for a realization of a charge qubit in double quantum dots.
[1] H. Imamura and P. A. Maksysm and H. Aoki, Phys. Rev. B. 59, 5817 (1999)
[2] S. Amaha and D. G. Austing and Y. Tokura and K. Muraki and K. Ono and S. Tarucha, Solid State Commun. 119, 183 (2001)