Study for realization of spin-polarized field effect transistor in In_0.75Ga_0.25As/In_0.75Al_0.25As heterostructure

For realization of the spin-polarized field effect transistor (spin-FET), we investigated a gated modulation of spin-orbit interaction and a spin-injection from a ferromagnetic metal (FM) to a two-dimensional electron gas (2DEG). Prepared samples were an In_0.75Ga_0.25As/In_0.75Al_0.25As modulation-doped narrow-gap heterojunction grown by molecular beam epitaxy (MBE). For the determination of spin-orbit interaction parameter, α, we measured Shubnikov-de Haas (SdH) oscillations at 1.5 K. We confirmed a modulation of α when a gate voltage was applied. We also carried out spin-injection experiments using a multi-terminal geometry sample, which had two different widths Ni₄₀Fe₆₀ electrodes. We observed a spin-valve like effect in a source-drain resistance of ∼ 0.1% as well as a resistance hysteresis behavior of ∼ 12% in non-local geometry below 20 K. These results are the first step to realize an active spintronic device, such as spin-FET.