The analysis of current fluctuations offers insight in the dynamics of electron transport which in contrast are unavailable in the observation of the average current. Our group has profound experience both in Shot Noise measurements (high frequency) and Full Counting Statistics (low frequency regime).
Shot Noise (Stochastic Fluctuations)
At low temperatures one of the most prominent current fluctuation phenomena is the so-called shot noise. It occurs at low transmission probabilities - e.g. transport through quantum dots or tunneling barriers - and has its origin in the discreteness of the electronic charge. Electron-electron interaction effects lead to an enhancement or suppression of the shot noise power allowing us to draw detailed conclusions about e.g. transmission probabilities, Coulomb blockade, or even many-body interaction effects like the Fermi edge singularity effect.
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AG Haug
Full Counting Statistics
While the shot noise offers insight about correlations in electronic transport through semiconductor heterostrucure devices it is a demanding task to extract higher moments directly from these measurements. In contrast those moments are naturally accessible in the context of Full Counting Statistics (FCS). Using a quantum point contact as a non-invasive detector, we are able to directly count the number of electrons leaving or entering a quantum dot system, allowing us to extract cumulants of the distribution up to the 20th order.
©
AG Haug