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HL: Halbleiterphysik

HL 12: Quantenpunkte und -dr
ähte: Transporteigenschaften I

HL 12.6: Vortrag

Montag, 26. März 2001, 16:45–17:00, S9/10

Interference and interaction effects in multi-level quantum dots — •Daniel Boese^1,2, Walter Hofstetter³, and Herbert Schoeller^2,1 — ¹Inst. für Theo. Festkörperphysik, Univ. Karlsruhe — ²Forschungszentrum Karlsruhe, Inst. für Nanotechnologie — ³Theo. Physik III, Institut für Physik, Univ. Augsburg

Using renormalization group techniques, we study spectral and transport properties of a spinless interacting quantum dot consisting of two levels coupled to metallic reservoirs. For strong Coulomb repulsion U and an applied Aharonov-Bohm phase φ, we find a large direct tunnel splitting |Δ|∼ (Γ/π)cos²(φ/2)ln(U/ω_c) between the levels of the order of the level broadening Γ. As a consequence we discover a many-body resonance in the spectral density which can be measured via the absorption power. Furthermore, we show that the system can be tuned into an effective Kondo model by changing the Aharonov-Bohm phase to φ=π.