电-声子耦合强度对量子点系统噪声的影响

利用Lang-Firsov正则变换和Keldysh非平衡格林函数方法研究了低温下具有电子-声子相互作用的量子点系统的噪声.我们特别注意了电-声子耦合强度的变化对量子点系统噪声的影响.数值结果表明:随着电-声子耦合强度的增大,系统的噪声增大,同时微分噪声谱中会出现一系列的声子伴带峰,峰的高度和数目对电-声子耦合强度的变化非常敏感.我们也研究了系统的Fano因子,它显示系统噪声对肖特基(Schottky)公式的偏离.在高偏压区,Fano因子随着电-声子耦合强度的增大而增大.

Influence of the Strength of electron-phonon coupling on Shot noise in a Quantum Dot system

We studied the shot noise of a system with a quantum dot coupled to a local phonon mode at low-temperature, using the Lang-Firsov canonical transformation and the Keldysh nonequilibrium Green function (NEGF) technique. We pay special attention to the influence of the strength of electron-phonon coupling on the shot noise. Our results show that the shot noise increases as the strength of electron-phonon coupling increases, meanwhile the differential shot noise exhibits several phonon-sideband peaks, and moreover, the height and number of the sideband peaks are sensitive to the strength of electron-phonon coupling. The Fano factor of the system is also studied, which exhibits the deviation of shot noise from the Schottky formula. In the high bias voltage region, the Fano factor is enhanced with increasing the strength of electron-phonon coupling.