(Poster) Interaction-induced charge and spin pumping through a quantum dot at finite bias

HERNAN L. CALVO; LAURA CLASSEN; JANINE SPLETTSTOESSER; MAARTEN R. WEGEWIJS

Bremen

Workshop; CECAM Workshop "Molecular electronics: Quo vadis?"; 2013

Deutsche Forschungsgemeinshaft

We discuss charge and spin transport through an adiabatically driven, strongly interacting quantum dot weakly coupled to two metallic contacts with finite bias voltage. We identify coefficients of response to the time-dependent external driving and relate these to the concept of emissivity. These coefficients allow for a straightforward analysis of the predicted interaction-induced pumping under periodic modulation of the gate and bias voltage. We extend this adiabatic Coulomb blockade spectroscopy to spin pumping. In the absence of a magnetic field, we show a striking, simple relation between the pumped charge at zero bias and at bias equal to the Coulomb charging energy. At finite magnetic field, we discuss the possibility to have interaction-induced pure spin pumping. For large-amplitude driving, the magnitude of both the pumped charge and spin saturates at values which are independent of the specific shape of the pumping cycle. Each of these values provides an independent, quantitative measurement of the junction asymmetry.