Tunneling current through a quantum dot with strong electron-phonon interaction

Abstract

The tunneling current through a quantum dot͑QD͒ in the presence of local electron-phonon interaction ͑EPI͒ and intradot Coulomb repulsion is studied theoretically for arbitrary strength of EPI. It is found that the renormalization of the intradot Coulomb repulsion and QD level position leads to intriguing effects on the tunneling current. The interplay of Coulomb blockade and phonon-assisted tunneling processes gives rise to a rich variety of tunneling current behavior.

Thermoelectric effect in an Aharonov-Bohm ring with an embedded quantum dot

“…It has been proved that similar to the electrical conductance, thermal transport in mesoscopic phonon systems also has a quantized unit ${\kappa }_{text\mathsf{\text{ph}}}MathClass-rel={\pi }^2{k}_B^{2}TMathClass-bin/\left(3h\right)$ at low temperature [1,2]. For higher temperature, electron-phonon interaction influences both the dot level position and dot-lead coupling strength [28,29] and has negative contribution to the magnitude of the figure-of-merit as is seen from its definition. Nevertheless, the Fano effect is robust against the presence of phonon [30], and we expect the enhanced thermoelectric efficiency will hold qualitatively true with such an interaction but with shifted dot levels' position and weakened magnitude.…”

Impact of electron-phonon coupling on electron transport through T-shaped arrangements of quantum dots in the Kondo regime

“…Interesting, similar effects have been also observed in the rigid structures of semiconductor quantum dots embedded in a freestanding GaAs/AlGaAs membrane [44][45][46][47][48]. It has been shown that morphology manipulation of semiconductor QDs such as size shape, strain distribution or inhomogenities can influence coupling strength of e-ph interaction [49]. The phononic effects exist not only in the sequential tunneling, but also in Kondo regime where the vibrational sidebands have been also observed [45,[50][51][52][53][54][55].…”

Impact of electron–phonon coupling on electron transport through T-shaped arrangements of quantum dots in the Kondo regime

“…In this approach the electron and phonon dynamics become decoupled. This approximation, which is widely used in literature [49,58,59,[70][71][72], predicts the exponential suppression of the tunneling amplitudes (Franck-Condon (F-C)-type suppression). Using the form of new fermion operators obtained in Lang-Firsov transformation it is easy to show that the electron Green's function of the dot can be decoupled as [73,74]: (8) where , , and or .…”

“…Interestingly, similar effects have been also observed in the rigid structures of semiconductor quantum dots embedded in a freestanding GaAs/AlGaAs membrane [ 44 – 48 ]. It has been shown that morphology manipulation of semiconductor QDs such as size, shape, strain distribution, or inhomogenities can influence the coupling strength of electron–phonon (e–ph) interactions [ 49 ]. The phononic effects appears not only in sequential tunneling, but also in the Kondo regime where vibrational sidebands have been also observed [ 45 , 50 – 54 ].…”