Spin Dependent Transport in an InAs Two Dimensional Electron Gas

Semiconductors, such as InAs, that exhibit a large spin orbit interaction (SOI), provide a mechanism to manipulate the spins in the semiconductor by precession in a Rashba field caused by an electric field generated with a gate. However a large SOI also implies short spin lifetimes, due to spin-relaxation caused by the interaction of impurities and crystal structure with the electron's spin orbit. To make a practical device out of a material with a short spin lifetime, you would need a high mobility in order to get a spin diffusion length that is on the length scales of your device. We designed a high mobility InAs 2deg (45 000 cm$^{2}$/V-sec @ 5K) and used tunnel barrier contacts (CoFe/Al$_{2}$O$_{3}$ and NiFe/Al$_{2}$O$_{3})$ to electrically inject and detect electron spin in the 2deg. We will show spin dependent transport in the 2DEG both in the spin-charge region and in the pure spin diffusion region using 3 terminal and nonlocal devices respectively.