Heat generated by electrical current in a mesoscopic system perturbed by alternating current fields

摘要

To analyze heat generation in a quantum dot coupled to normal leads and subject to an ac field, a formula is derived for the heat generated Q using the nonequilibrium Keldysh Green's function technique. The numerical results show that the external ac field influences significantly the heat generated. The threshold bias decreases to V_t=ω₀-nω through photon absorption. Additional steps emerge from photon-assisted tunneling, and the width of the step is equal to the frequency of photon ω and the height increases with the magnitude of the ac field. For large V/ω, the Q/ω curves display many resonant peaks due to multi-photon absorptions and emissions. Moreover, a negative differential heat generation can be observed as ω>ω₀.