Screening effects in the interplay between thermoelectric response and time-dependent driving
We investigate a coherent conductor, which is voltage- and temperature-biased and additionally fed by a time-dependently driven single-particle source (SPS). The conductor has an energy-dependent transmission that we propose to be realized by a quantum point contact (QPC). The interplay between stationary biases and time-dependent driving results in (quantum) screening effects at the QPC, which are already visible in the linear thermoelectric response coefficients of the conductor to small biases and which can literally be switched on and off by the presence or absence of the time-dependent driving. We find that this effect opens up for two very different opportunities for spectroscopy: (1) the linear-response coefficients modified by the source operation give direct access to rather unexplored quantum screening effects, which in other types of devices are obscured by geometric capacitive effects and only constitute negligibly small corrections. At the same time, (2) the tunable screening corrections to the linear-response coefficients are related to the energetic properties of the SPS, providing a direct experimental characterization tool for the SPS properties.