Lifting the Franck-Condon blockade in driven quantum dots

Haughian, Patrick; Walter, Stefan; Nunnenkamp, Andreas; Schmidt, Thomas L.

doi:10.1103/physrevb.94.205412

Cited by 6 publications

(17 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, the exponential factor is familiar from the lifting of Franck-Condon blockade in the unbiased case of our model. 33 Hence we conclude that the polaron dot exhibits pumping characteristics similar to a non-interacting system, in addition to FranckCondon blockade and strong amplification of pump current by application of an AC gate voltage.…”

Section: Polaron Pumpingmentioning

confidence: 66%

“…This result also serves to confirm earlier work on drive-induced lifting of Franck-Condon blockade, where only time-averaged correlation functions were considered in the perturbative expansion. 33 Secondly, we applied the same formalism to the unbiased quantum dot. There, the interplay between both dot and coupling drives makes it possible to pump a DC current through the system: Similar to the case of charge pumping in purely electronic systems, we find that in the regime of weak dot drive the DC current flow is approximately proportional to the drive amplitude, as long as a phase difference between the left and right coupling drives is employed to break left-right symmetry.…”

Section: Discussionmentioning

confidence: 99%

“…Application of an AC voltage to the dot energy can supply the energy required to break up the polaron, thus facilitating electron tunneling and lifting the current blockade. 33 In the following, we set up a formalism that allows us to treat periodic, resonant drives in both the dot energy (t) and the coupling to the leads V kα (t).…”

Section: Modelmentioning

confidence: 99%

“…33 Moreover, the coupling is driven at half of this frequency, so that the self-energy, which contains the square of the coupling, is itself in resonance with the dot and the vibron. According to Eq.…”

Section: Current Under Biasmentioning

confidence: 99%

“…33 In Ref. [33], it was proposed to observe this effect in a CNT quantum dot, since such a system exhibits the required strong coupling, and the AC gate voltage could be supplied by the gates used to define the quantum dot. 34 Here, we extend this setup by using additional gates to also modulate the coupling of the quantum dot to the lead electrodes.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Charge pumping in strongly coupled molecular quantum dots

et al. 2017

Self Cite

View full text Add to dashboard Cite

The interaction between electrons and the vibrational degrees of freedom of a molecular quantum dot can lead to an exponential suppression of the conductance, an effect which is commonly termed Franck-Condon blockade. Here, we investigate this effect in a quantum dot driven by time-periodic gate voltages and tunneling amplitudes using nonequilibrium Green's functions and a Floquet expansion. Building on previous results showing that driving can lift the Franck-Condon blockade, we investigate driving protocols which can be used to pump charge across the quantum dot. In particular, we show that due to the strongly coupled nature of the system, the pump current at resonance is an exponential function of the drive strength.

show abstract

Section: Polaron Pumpingmentioning

confidence: 66%

Section: Discussionmentioning

confidence: 99%

Section: Modelmentioning

confidence: 99%

Section: Current Under Biasmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Charge pumping in strongly coupled molecular quantum dots

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

Quantum turnstile regime of nanoelectromechanical systems

Dragomir¹,

Moldoveanu²,

Stanciu³

et al. 2020

Phys. Rev. B

View full text Add to dashboard Cite

The effects of a turnstile operation on the current-induced vibron dynamics in nanoelectromechanical systems (NEMS) are analyzed in the framework of the generalized master equation. In our simulations each turnstile cycle allows the pumping of up to two interacting electrons across a biased mesoscopic subsystem which is electrostatically coupled to the vibrational mode of a nanoresonator. The time-dependent mean vibron number is very sensitive to the turnstile driving, rapidly increasing/decreasing along the charging/discharging sequences. This sequence of heating and cooling cycles experienced by the nanoresonator is due to specific vibron-assisted sequential tunneling processes along a turnstile period. At the end of each charging/discharging cycle the nanoresonator is described by a linear combination of vibron-dressed states sν associated to an electronic configuration ν. If the turnstile operation leads to complete electronic depletion the nanoresonator returns to its equilibrium position, i.e. its displacement vanishes. It turns out that a suitable bias applied on the NEMS leads to a slow but complete cooling at the end of the turnstile cycle. Our calculations show that the quantum turnstile regime switches the dynamics of the NEMS between vibron-dressed subspaces with different electronic occupation numbers. We predict that the turnstile control of the electron-vibron interaction induces measurable changes on the input and output transient currents.

show abstract

Quantum transport in driven systems with vibrations: Floquet nonequilibrium Green's functions and the self-consistent Born approximation

Honeychurch

Kosov

2023

Phys. Rev. B

View full text Add to dashboard Cite

We study the dynamics of two capacitively coupled quantum dots, each coupled to a lead. A Floquet Green's function approach described the system's dynamics, with the electron-electron interactions handled with the fluctuation-exchange approximation. While electrons cannot move between the separate sections of the device, energy transfer occurs with the periodic driving of one of the leads. This process was found to be explained with four stages. The energy transfer was also found to be sensitive to the driving frequency of the leads, with an optimal frequency corresponding to the optimal completion of the four stages of the identified process.

show abstract

Lifting the Franck-Condon blockade in driven quantum dots

Cited by 6 publications

References 37 publications

Charge pumping in strongly coupled molecular quantum dots

Charge pumping in strongly coupled molecular quantum dots

Quantum turnstile regime of nanoelectromechanical systems

Quantum transport in driven systems with vibrations: Floquet nonequilibrium Green's functions and the self-consistent Born approximation

Contact Info

Product

Resources

About