Optimizing motion-induced spin transfer

運動誘起スピン移行の最適化

大上 能悟*; 松尾 衛

Oue, Daigo*; Matsuo, Mamoru

In this article, the spin transfer between two ferromagnetic insulators is studied. There is a narrow gap between the ferromagnetic insulators so that they are weakly interacting with each other. One of the ferromagnetic insulators is moving at a constant speed while the other is at rest; hence, the system is out of equilibrium. In the presence of the shearing motion, the interaction amplitude is periodically modulated at the Doppler frequency. A unitary transformation allows us to regard the periodic modulation of the interaction amplitude as an effective potential, which drives the spin transfer. The amount of the spin current is controlled by the spectral overlap and the carrier population difference between the two ferromagnetic media. If the spectra of the two ferromagnets are moderately broadened, the overlap in the spectral domain increases, enlarging the spin current.