Eur. Phys. J. B (2013) 86: 16
https://doi.org/10.1140/epjb/e2012-30860-0

Regular Article

Electron transport through a quantum dot in the presence of electron-photon and electron-phonon coupling

Department of Physics, Quaid-i-Azam University, 49000 Islamabad, Pakistan

^a e-mail: imran1gee@gmail.com

Received: 20 September 2012
Received in final form: 12 October 2012
Published online: 21 January 2013

Abstract

In this study, electron transport through a mesoscopic quantum dot system (QD-system) in the presence of electron-photon (el-pt) and electron-phonon (el-ph) interactions is discussed. The role of both of these interactions is to induce additional steps in the current, and sideband peaks in the differential conductance. By calculating the current and differential conductance of a QD-system in the presence of el-pt or el-ph coupling, we have shown that photon or phonon steps and sideband peaks are induced in the current and differential conductance whenever the applied voltage resonates with their frequency. Furthermore, additional side band peaks are induced in the differential conductance when el-pt and el-ph interactions are simultaneously included in the QD. These extra sideband peaks (ESBPs) are induced when the applied voltage and the photon frequency are in close proximity with the phonon frequency. To investigate the relationship that exists between the photon and phonon frequency in inducing ESBPs in the differential conduction, we have discussed zero applied voltage differential conductance. Under such conditions, ESBP is induced only when the photon frequency resonates with the phonon frequency. With increasing el-ph coupling amplitude, more ESBPs are induced in the differential conductance.