1,237 research outputs found
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 on the photon polarization, but
it is not strongly dependent on the average number of photons in the
environment.Comment: RevTeX, 9 pages with 10 included eps figure
Manifestation of the Purcell effect in current transport through a dot-cavity-QED system
We study the transport properties of a wire-dot system coupled to a cavity
and a photon reservoir. Tuning the photon energy, Rabi-resonant states emerge
and in turn resonant current peaks are observed. We demonstrate the effects of
the cavity-photon reservoir coupling, the mean photon number in the reservoir,
the electron-photon coupling and the photon polarization on the intraband
transitions occurring between the Rabi-resonant states, and on the
corresponding resonant current peaks. The Rabi-splitting can be controlled by
the photon polarization and the electron-photon coupling strength. In the
selected range of parameters, we observe the results of the Purcell effect
enhancing the current peaks through the cavity by increasing the
cavity-reservoir coupling, while they decrease with increasing the
electron-photon coupling. In addition, the resonant current peaks are also
sensitive to the mean number of photons in the reservoir.Comment: RevTeX, 8 pages with 7 included eps figure
Thermoelectric inversion in a resonant quantum dot-cavity system in the steady-state regime
The thermoelectric effect in a quantum dot system connected to two electron
reservoirs in the presence of a photon cavity is investigated using a quantum
master equation in the steady-state regime. If a quantized photon field is
applied to the quantum dot system, an extra channel, the photon replica states,
are formed leading to a generation of 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 photon energy is smaller than the energy difference between
the lowest states of the quantum dot system, a current plateau is seen for
strong electron-photon coupling. 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.Comment: RevTeX, 8 pages with 9 included eps figure
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