We derive formal expressions of time-dependent energy and heat currents through a non-interacting mesoscopic device using the Keldysh nonequilibrium Green function technique. Numerical results are reported for a metal/dot/metal junction where the dot level energy is abruptly changed by a step-shaped voltage pulse. Analytical linear responses are obtained for time-dependent thermoelectric coefficients. We show that the Seebeck coefficient can be enhanced in the transient regime up to an amount controlled by both the dot energy and the height of the voltage step.

Université Aix-Marseille II