Observation of spin polarized transport across a ferromagnet-two-dimensional electron gas interface (invited)

Spin injection at a ferromagnet-semiconductor interface has been demonstrat ed by convolving the spin-split density of states of carriers in a high mob ility InAs quantum well with the spin polarization of conduction electrons in a thin ferromagnetic film. Transport measurements on a diode structure d etected a spin-dependent interfacial resistance, with Delta R-i/(R) over ba r(i)approximate to 1%. In a different configuration, open circuit voltage e xperiments measure the spin-dependent shifts in the chemical potential of t he carriers in the quantum well. Results of the two techniques are compared over the temperature range 50 < T < 296 K, demonstrating both spin injecti on and detection at the ferromagnet-semiconductor interface. [S0021-8979(00 )61408-1].