Conversion efficiency of spin power to charge power in a normal metal with spin-orbit coupling

Abstract We theoretically investigate the conversion efficiency of spin power to charge power in a normal metal with spin-orbit coupling based on the Green's function method. The normal metal is connected with three leads. A spin current injected in one lead can induce a charge current between another two leads. We find that the conversion efficiency of spin power to charge power is roughly proportional to t SO 4 when the spin-orbit coupling t SO is weak, suggesting that the efficiency is limited. Moreover, an increase of temperature may reduce the efficiency. The results may be useful in determining the overall efficiency of a thermoelectric setup based on the longitudinal spin Seebeck effect.