Electrical spin injection into AlGaAs/GaAs-based two-dimensional electron gas systems with Co2MnSi spin source up to room temperature

We demonstrated electrical spin injection into an AlGaAs/GaAs-based high-mobility two-dimensional electron gas (2DEG) system using Co2MnSi as a spin source. A non-local spin-valve signal was observed from 4.2 K to room temperature. Interestingly, the spin-valve signal does not show a monotonic decrease with increasing temperature and reaches a peak at about 80 K. This contrasts with the result observed in bulk GaAs, in which a monotonic decrease in spin-valve signals with increasing temperature was observed. Moreover, the spin-valve signal decreases by a factor of about 5.6 with increasing temperature from 4.2 K to 294 K, and this factor is smaller than those values reported in bulk GaAs devices. This result suggests that the spin-valve signal in a 2DEG device is less sensitive to temperature than that in a bulk device, which is promising for realizing future spin transistors that can operate at room temperature.