https://doi.org/10.1140/epjb/e2012-30027-1
Regular Article
Quantum transport of double quantum dots coupled to an oscillator in arbitrary strong coupling regime
1
Department of Physics, Zhejiang University,
Hangzhou
310027, P.R.
China
2
Department of Physics and Centre for Computational Science and
Engineering, National University of Singapore, Singapore
117546, Republic of
Singapore
3
NUS Graduate School for Integrative Sciences and
Engineering, Singapore
117456, Republic of
Singapore
4
Center for Statistical and Theoretical Condensed Matter Physics,
Zhejiang Normal University, Jinhua
321004, P.R.
China
a e-mail: jieustc@gmail.com
b e-mail: phylibw@nus.edu.sg
b e-mail: zqhchen@zju.edu.cn
Received:
10
January
2012
Received in final form:
13
February
2012
Published online:
30
March
2012
In this paper, we investigate the quantum transport of a double quantum dot coupled with a nanomechanical resonator at arbitrary strong electron-phonon coupling regimes. We employ the generalized quantum master equation to study full counting statistics of currents. We demonstrate the coherent phonon states method can be applied to decouple the electron-phonon interaction non-perturbatively. With the help of this non-perturbative treatment of electron-phonon couplings, we find that the phonon-assisted resonant tunneling emerges when the excess energy from the left quantum dot to the right one can excite integer number of phonons and multi-phonon excitations can enhance the transport in strong electron-phonon coupling regime. Moreover, we find that as the electron-phonon coupling increases, it first plays a constructive role to assist the transport, and then plays the role of scattering and strongly represses the transport.
Key words: Mesoscopic and Nanoscale Systems
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2012