Time-dependent thermoelectric transport in mesoscopic systems under a quantum quench

Abstract

We investigate the transient behavior of the quantum transport in mesoscopic systems under a quantum quench within the Caroli scheme. Using the nonequilibrium Green's function approach, an exact solution of the transient electric current, energy current, and their fluctuations in the presence of both external bias and temperature gradient are presented that goes beyond the wide-band limit. The exact solution of the time-dependent Seebeck coefficient in the linear response regime is also obtained. This formalism is applied to study the transient behavior of a single-level quantum dot with Lorentzian linewidth induced by the temperature gradient. The damped oscillatory behavior is found in the transient electric and energy currents, as well as their fluctuations. The oscillation frequency of electric and energy currents increases with the increasing energy level of quantum dot and the decay rate of oscillation decreases as the bandwidth increases. A significantly enhanced Seebeck coefficient is generated in the transient regime. We find the maximum value of the time-dependent Seebeck coefficient can be enhanced by increasing the energy level of the quantum dot and the reference temperature of leads.