Non-classical state effect on the persistent current in one-dimensional mesoscopic ring with electron-phonon interaction

Based on the efficacy of the phonon coherent state and with consideration of the non-classical effect of the squeezed state of phonon, the influence of the electron-magnon interaction and the electron-phonon interaction on the persistent current in one-dimensional mesoscopic ring is studied. Compared with the free ring, our study shows that in one-dimensional mesoscopic ring, the amplitude of the persistent current exponentially diminishes due to the electron-magnon interaction. For the normal state electron, the interaction of the electron-phonon causes the persistent current to weakendce to the Debye-Waller effect. However, taking the correlation between the hopping electron states and the one-phonon coherent states into the equation, the ground energy of the mesoscopic system is declined in a large scale. In result, the persistent current In is increased substantially. On the other hand, taking the behavior of the two-phonon coherent state into account, as the effect of the squeezed states of phonons maintains the phase coherence of electrons, so the Debye-Waller attenuation is weakened effectively. Especially, when the squeezed angle is larger, because of the non-adiabatic correlation between the squeezed-phonon states and the coherent states of phonon, it causes a significant decline in the ground state energy and a significant increase in the squeezed angle, thus persistent current has a even more significant increase. It should be pointed out, that the persistent current shows period oscillation as the external magnetic flux changes. Even the external magnetic flux Φem=0, still the persistent current of the intrinsic has I ~ n≠0. The system continuoues to support the equilibrium spin and charge flow, the external magnetic flux only plays the role of an adiabatic parameter.