Dresden 2026 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 17: Quantum Dots and Wires: Rings, Wires and Transport
HL 17.6: Talk
Tuesday, March 10, 2026, 10:45–11:00, POT/0251
Quantum dot as a model system for a Hund’s coupled impurity — •Olfa Dani1, Johannes C. Bayer1,2, Timo Wagner1, Gertrud Zwicknagl3, and Rolf J. Haug1 — 1Institut für Festkörperphysik, Leibniz Universität Hannover, Hannover, Germany — 2Physikalisch-Technische Bundesanstalt, Braunschweig, Germany — 3Institut für Mathematische Physik, Technische Universität Braunschweig, Braunschweig, Germany
In this work, we investigate electron transport through the third shell [1] of a gate-defined GaAs quantum dot, where the exact electron number (N) is determined using a quantum point contact and tuned in a controlled manner by changing the applied gate voltages of the device [2]. For N = 7-11, the addition energy shows a triangular evolution with a maximum at half-filling. This trend is reproduced by model calculations including Hund’s rule exchange. In the same filling range, a zero-bias anomaly (ZBA) characteristic of the Kondo effect appears. Its width and amplitude display a similar triangular dependence, reflecting the particle-hole symmetry of the three spin-degenerate orbitals. The pronounced ZBA is attributed to the contribution of both the Kondo resonance and low-energy Hund satellite excitations associated with degenerate orbitals observed in the spectral function [3]. The quantum dot is viewed as a multi-orbital Kondo impurity with Hund’s interaction and serves as a model system for a Hund’s coupled impurity. [1] L. P. Kouwenhoven, et. al., Rep. Prog. Phys. 64 (2001). [2] T. Wagner, et. al., Nat. Phys.15 (2019). [3] O. Dani, et. al., arXiv: 2505.21675 (2025).
Keywords: Quantum transport; Quantum dots; Coulomb blockade; Kondo effect