Delocalization of electrons by cavity photons in transport through a quantum dot molecule
Abstract
We present results on cavityphotonassisted electron transport through two lateral quantum dots embedded in a finite quantum wire. The double quantum dot system is weakly connected to two leads and strongly coupled to a single quantized photon cavity mode with initially two linearly polarized photons in the cavity. Including the full electronphoton interaction, the transient current controlled by a plungergate in the central system is studied by using quantum master equation. Without a photon cavity, two resonant current peaks are observed in the range selected for the plunger gate voltage: The ground state peak, and the peak corresponding to the firstexcited state. The current in the ground state is higher than in the firstexcited state due to their different symmetry. In a photon cavity with the photon field polarized along or perpendicular to the transport direction, two extra side peaks are found, namely, photonreplica of the ground state and photonreplica of the firstexcited state. The sidepeaks are caused by photonassisted electron transport, with multiphoton absorption processes for up to three photons during an electron tunneling process. The interdot tunneling in the ground state can be controlled by the photon cavity in the case of the photon field polarized along the transport direction. The electron charge is delocalized from the dots by the photon cavity. Furthermore, the current in the photoninduced sidepeaks can be strongly enhanced by increasing the electronphoton coupling strength for the case of photons polarized along the transport direction.
 Publication:

Physica E LowDimensional Systems and Nanostructures
 Pub Date:
 November 2014
 DOI:
 10.1016/j.physe.2014.07.030
 arXiv:
 arXiv:1403.0382
 Bibcode:
 2014PhyE...64..254A
 Keywords:

 Condensed Matter  Mesoscale and Nanoscale Physics
 EPrint:
 Physica E 64, 254262 (2014)