Dynamical spin injection into a two-dimensional electron gas in an AlGaAs/GaAs structure

A two-dimensional electron system in a GaAs-based heterostructure is the attractive platform for spintronics since it has high mobility and spin-orbit interaction can be modulated by the gate voltage$^1$. Thus, it is a possible platform to realize electric gate-controlled spin transistor$^2$. However, room-temperature spin transport through GaAs-based heterostructure has yet to be shown. We report first spin transport through the quantum well at GaAs/AlGaAs interface at room temperature. We used spin pumping under ferromagnetic resonance to inject spins from the Ni$_{80}$Fe$_{20}$ to the GaAs/AlGaAs quantum well. Generated spin current propagated through the 1 $\mu$m channel and was detected using spin-charge conversion inverse spin Hall effect in the Pt electrode. In agreement with spin pumping theory, polarity of the spin transport signal was reversed together with magnetization of the Ni$_{80}$Fe$_{20}$. This first demonstration of spin transport through a quantum well at a semiconductor heterostructure interface at room temperature opens a way to realize Datta-Das spin-based transistor.\\ \\ $^1$ J. Nitta, et al., PRL 78, 1335 (1997).\\ $^2$ S. Datta and B. Das, Appl. Phys. Lett. 56, 665 (1990).