Photon-Mediated Thermoelectric and Heat Currents through a Resonant Quantum Wire-Cavity System

The photocurrent generated by photon replica states of an off-resonantly coupled dot-cavity system

Transport properties of a quantum dot coupled to a photon cavity are investigated using a quantum master equation in the steady-state regime. In the off-resonance regime, when the photon energy is smaller than the energy spacing between the lowest electron states of the quantum dot, we calculate the current that is generated by photon replica states as the electronic system is pumped with photons. Tuning the electron-photon coupling strength, the photocurrent can be enhanced by the influences of the photon polarization, and the cavity-photon coupling strength of the environment. We show that the current generated through the photon replicas is very sensitive to the photon polarization, but it is not strongly dependent on the average number of photons in the environment.

Thermoelectric Inversion in a Resonant Quantum Dot-Cavity System in the Steady-State Regime

We theoretically investigate thermoelectric effects in a quantum dot system under the influence of a linearly polarized photon field confined to a 3D cavity. A temperature gradient is applied to the system via two electron reservoirs that are connected to each end of the quantum dot system. The thermoelectric current in the steady state is explored using a quantum master equation. In the presence of the quantized photons, extra channels, the photon replica states, are formed generating a photon-induced thermoelectric current. We observe that the photon replica states contribute to the transport irrespective of the direction of the thermal gradient. In the off-resonance regime, when the energy difference between the lowest states of the quantum dot system is smaller than the photon energy, the thermoelectric current is almost blocked and a plateau is seen in the thermoelectric current for strong electron–photon coupling strength. In the resonant regime, an inversion of thermoelectric current emerges due to the Rabi-splitting. Therefore, the photon field can change both the magnitude and the sign of the thermoelectric current induced by the temperature gradient in the absence of a voltage bias between the leads.