Berlin 2005 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
HL: Halbleiterphysik
HL 45: Quantenpunkte und -dr
ähte: Transporteigenschaften II
HL 45.2: Vortrag
Montag, 7. März 2005, 15:15–15:30, TU P-N202
Shot noise measurements at the Fermi Edge Singularity of InAs quantum dots — •N. Maire1, T. Lüdtke1, R. J. Haug1, and K. Pierz2 — 1Institut für Festkörperphysik, Universität Hannover, D-30167 Hannover — 2Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig
We investigate the noise properties of self-assembled InAs quantum dots embedded into a GaAs-AlAs-GaAs heterostructure. The I-V-characteristic shows a step-like dependence which can be directly linked to resonant tunneling through the ground states of single quantum dots. This allows us to measure the noise properties of single 0-dimensional states. We furthermore observe a strong overshoot of the current amplitude of a particular step with increasing magnetic fields and decreasing temperatures which we interpret as an electron-electron interaction effect, a so called Fermi Edge Singularity (FES).
The resulting noise power shows a frequency independent spectrum, the so called shot noise. This noise power is suppressed compared to the theoretical value 2eI of a single tunneling barrier as it is indeed expected for a double barrier resonant tunneling structure. This suppression is characterized by the dimensionless Fano factor α =S/2eI; S being the average noise power density. We now analyze the FES in detail by measuring the Fano Factor for increasing magnetic fields up to 15 T and varying temperatures down to approx. 300 mK and compare the results with theoretical predictions.