Probing the two-electron-interaction-induced three new hopping processes in a double quantum-dot system revealed by finite-frequency shot noise

Abstract

In the serially coupled double quantum dot (DQD) system, the two-electron-interaction-induced electron hopping processes and spin-exchange hopping processes play a crucial role in manipulating the spin degree of freedom of localized electrons in the DQD system. Consequently, from the perspective of electron transport, how to detect the new hopping processes induced by the two-electron interaction has become an increasingly important issue. Here, the influences of the three new hopping processes predicted by the generalized Hubbard model on the finite-frequency shot noise of electron transport through a serially coupled DQD system are studied. It is demonstrated that in the energy-level detuning case the criterion for the existence of the electron-occupation-modulated hopping processes is that the maximum number of peaks and dips of the finite-frequency shot noise equals eight while in the energy-level alignment case the criteria for the existence of the two-electron-interaction-induced three new hopping processes, and the antiparallel-electron-spin-exchange hopping and electron-pair hopping processes, and the electron-occupation-modulated hopping processes are that the maximum numbers of peaks and dips equal eight, seven, and six, respectively. Therefore, these results provide an alternative way to detect the three new hopping processes predicted by the generalized Hubbard model in the serially coupled DQD system.