The Influence Of Rashba Spin-Orbit Coupling On Phonon-Assisted Tunneling

In this thesis, within the framework of an effective mass approximation, the phonon-assisted tunneling has been investigated by considering the longitudinal optical phonon modes localized in a well. The role of Rashba spin-orbit coupling in phonon-assisted tunneling is discussed in detail as well.The confined phonon emission rate and tunneling current in AlxGa1-xAs/GaAs/AlxGa1-xAs symmetric double barrier structures are calculated by using the transfer-matrix method and the Fermi golden rule. The results show that the well-longitudinal optical phonon emission rate and phonon assisted tunneling current densities both split clearly due to spin orbit coupling. The peak values of phonon emission rate and phonon assisted tunneling current become smaller for a spin-up electron; the opposite happens for a spin-down electron. Moreover, it can be found that the peaks of phonon assisted tunneling current with spin orbit coupling are smaller than that without spin orbit coupling. Additionally, the positions of the peaks of phonon assisted tunneling current do not change, regardless whether or not considering a spin orbit coupling. The peaks of phonon emission rate curve occur at the energy level separation36.25meV, which corresponds to the well-longitudinal optical phonon energy. It is also found that the influences of Rashba spin orbit coupling on phonon assisted tunneling of a spin-down electron are more remarkable than that for a spin-up electron.