Persistent spin currents in a triple-terminal quantum ring with three arms

A new model of a triple-terminal quantum ring with three arms is proposed.We develop an equivalent method for reducing the triple-terminal quantum ring to the double-terminal quantum ring and calculate the persistent spin currents in this model.The results indicate that the persistent spin currents show behavior of nonperiodic and unequal amplitude oscillation with increasing semiconductor ring size when the total magnetic flux is zero. However,when the total magnetic flux is non-zero,the persistent spin currents make periodic equal amplitude oscillations with increasing AB magnetic flux intensity.At the same time,the two kinds of spin state persistent spin currents have the same frequency and amplitude but the inverse phase.In addition,the Rashba spin-orbit interaction affects the phase and the phase difference of the persistent spin currents.The average persistent spin currents relate to the arm length and the terminal position as well as the distribution of the magnetic flux in each arm.Furthermore, our results indicate that the AB magnetic flux has different influences on the two kinds of spin state electrons.