Regensburg 2019 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 22: Quantum dots and wires: Transport properties

HL 22.4: Talk

Tuesday, April 2, 2019, 14:45–15:00, H34

Local Density of States Fluctuations and Its Influence on the Fermi-edge-singularity in a Quantum Dot — •Jan K. Kühne and Rolf J. Haug — Institut für Festkörperphysik, Leibniz Universität Hannover, Deutschland

Transport measurements in quantum dots can be used as a spectrometer to study the density of states in the connected leads [1]. By tuning the applied source drain voltage, the current through the quantum dot is changed depending on the number of available states in both leads with the corresponding energy.

We study the transport properties of a self-assembled InAs quantum dot at low temperatures and observe strong fluctuations in the local density of states (LDOS) in dependence of magnetic field B and voltage V. This results in lines of constant differential conductance with a constant slope dB/dV. It is known that interaction effects in quantum dots, such as the Fermi-edge-singularity (FES), strongly depend on the dimensionality and the density of states in the leads [2]. By comparing the LDOS and the interaction due to the FES we find a clear anti-correlation between the strength of the FES and the number of states in the emitter.

[1] T. Schmidt, et al., Phys. Rev. Lett. 78, 1540 (1997).

[2] J. K. Kühne, et al., accepted in Phys. Status Solidi B (2018).