Vendredi 05 juillet 2013 à 13h45
Auditoire Stueckelberg, Ecole de Physique

Current and noise in an adiabatically driven interacting quantum dot

Janine Splettst, RWTH Aachen, Germany

I will present recent work on charge and spin transport [1] and the related transport noise [2] for an adiabatically driven single-level quantum dot with strong Coulomb interaction, possibly in the presence of a voltage bias. Within a kinetic equation approach, we identify coefficients of response to the time-dependent external driving and relate these to the concepts of charge and spin emissivities previously discussed within the time-dependent scattering matrix approach [3]. Expressed in terms of auxiliary vector fields, the response coefficients allow for a straightforward analysis of recently predicted interaction-induced pumping under periodic modulation of the gate and bias voltage [4]. We perform a detailed study of this effect and the related adiabatic Coulomb blockade spectroscopy, and, in particular, extend it to spin pumping. In addition we study the zero-frequency noise for this single-level quantum dot driven by different sets of driving parameters. If no stationary bias is applied, the adiabatic correction shows Coulomb-interaction-induced deviations from the fluctuation-dissipation theorem. Furthermore, we show that the adiabatic correction to the Fano factor carries information about the coupling asymmetry and is independent of the choice of the pumping parameters. When including a time-dependent finite bias, we find that there can be pumping noise even if there is zero adiabatically pumped charge. This can be interpreted using the properties of the pseudomagnetic fields identified in the pumped charge before. [1] H. Calvo, L. Classen, J. Splettstoesser, and M. R. Wegewijs, Phys. Rev. B 86, 245308 (2012). [2] R.-P. Riwar, J. Splettstoesser, and J. K"onig, Phys. Rev. B 87, 195497 (2013). [3] M. B"uttiker, H. Thomas, and A. Pr^etre, Z. Phys. B 94, 133 (1994). [4] F. Reckermann, J. Splettstoesser, and M. R. Wegewijs, Phys. Rev. Lett. 104, 226803 (2010).