Detection of spin-polarized electrons injected into a two-dimensional electron gas

The spin-dependent mean-free path of electrons in a high-mobility InAs two-dimensional electron gas (2DEG) is measured. Ferromagnetic metal/insulator/2DEG junctions are fabricated on a common channel in a nonlocal geometry and used as spin injectors and detectors. For electrons in spin-orbit eigenstates at 4.5 K, lower bounds for the spin mean-free path and relaxation time are Lambda(S) greater than or equal to 4.6 mum and tau(s) greater than or equal to 3.8 ps, respectively. The temperature dependence is weak over the range 4.5 < T < 150 K.