The electric current induced heat generation in a strongly interacting quantum dot in the Coulomb blockade regime

TL;DR

This paper investigates how electric current induces heat in a strongly interacting quantum dot, revealing complex behaviors influenced by phonon frequency and Coulomb blockade effects, with implications for device efficiency.

Contribution

It provides a detailed analysis of heat generation mechanisms in quantum dots considering electron-electron and electron-phonon interactions using non-equilibrium Green's functions.

Findings

Heat generation proportional to current at low phonon frequency

Non-monotonic heat generation behavior at high phonon frequency

Large heat generation in Coulomb blockade region despite small current

Abstract

The heat generation by an electric current flowing through a quantum dot with the dot containing both electron-electron interaction and electron-phonon interaction, is studied. Using the non-equilibrium Keldysh Green's function method, the current-induced heat generation is obtained. We find that for a small phonon frequency, heat generation is proportional to the current. However, for a large phonon frequency, heat generation is in general qualitatively different from the current. It is non-monotonic with current and many unique and interesting behaviors emerge. The heat generation could be very large in the Coulomb blockade region, in which the current is very small due to the Coulomb blockade effect. On the other hand, in the resonant tunneling region, the heat generation is very small despite a large current, an ideal condition for device operation. In the curve of heat generation versus the bias, a negative differential of the heat generation is exhibited, although the current is always monotonously increasing with the bias voltage.