Regensburg 1998 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 11: Quantenpunkte I

HL 11.7: Vortrag

Montag, 23. März 1998, 17:30–17:45, H1

Conductance oscillations and periodic orbits in a triangular quantum dot — •K. Tanaka and M. Brack — Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg

We analyze periodic magnetoconductance fluctuations that have recently been measured in a quantum dot with triangular confinement in a perpendicular homegeneous magnetic field [1]. As in Ref. [2], we assume the conductance to be dominated by the tunneling probability of the electrons and thus to be proportional to the density of bound single-particle states within the confinement region. A semiclassical analysis of the level density in terms of periodic orbits is given for two models for the total effective (Kohn-Sham) potential: a) a triangular billiard with reflecting walls, which is integrable, and b) a smooth potential of Hénon-Heiles type, which exhibits chaotic classical dynamics at higher energies and for which the semiclassical periodic orbit theory has been shown to reproduce the level density fluctuations quantitatively [3].

[1] P. Bøggild et al., NBI Copenhagen Preprint (1997).

[2] S. M. Reimann et al., Z. Phys. B 101, 377 (1996); M. Brack et al., Z. Phys. D 40, 276 (1997).

[3] M. Brack et al., Chaos 5, 317,707 (1995); M. Brack, S. Creagh and J. Law, Phys. Rev. A (1997) in print.