Fabrication of spin-injection transistor and its application to quantum computing devices

We have verified large spin-orbit coupling in InAs quantum well structure which was grown on InAs substrate by analyzing Shubnikov-de Haas oscillation。The obtained spin-orbit interaction coefficient was[similar or equal]2.7x10^&lt；-11&gt；eVm。The number was found to be much greater than that of GaAs or InGaAs on InP and almost comparable to the previous experiments where measured InAs heterostructures were associated with possible effects from interface states or possible residual strain or possible interplay of several sublevels。The present result verified that these possible effects has minor effects and anisotropic InAs heterostructures have unusually large spin-orbit coupling which cannot be explained by simple perturbation theories such as k·p calculation.We have also discovered a new method of evaluating“spin-gap”caused by spin-orbit interactions through interband tunneling current analysis.for the the spin-jromagnetic the figrougis of through interband tunneling currating of the through interband tunneling currating，these result verified thatects and thesk.We have also investigated the electroluminescence of spin polarized electrons injected from ferromagnets into InAs therough Fe/InAs junction，and verified spin injection is possible with polarization of[similar or equal]4%which is the first report with barrierless junction between ferromagnet and semiconductor and even one of the highest number reported by reliable experiments.

We have verified large spin-orbit coupling in InAs quantum well structure which was grown on InAs substrate by analyzing Shubnikov-de Haas oscillation. The obtained spin-orbit interaction coefficient was 【similar or equal】 2.7x10^<-11>eVm. The number was found to be much greater than that of GaAs or InGaAs on InP and almost comparable to the previous experiments where measured InAs heterostructures were associated with possible effects from interface states or possible residual strain or possible interplay of several sublevels. The present result verified that these possible effects has minor effects and anisotropic InAs heterostructures have unusually large spin-orbit coupling which cannot be explained by simple perturbation theories such as k・p calculation.We have also discovered a new method of evaluating "spin-gap" caused by spin-orbit interactions through interband tunneling current analysis.As for the "spin-injection" from ferromagnetic film into semiconductors, we have investigated the crystal Fe growth on InAs by molecular beam epitaxy and electromagnetic characteristics of the ferromagnetic firm and stripes grown on InAs. We have also investigated the electroluminescence of spin polarized electrons injected from ferromagnets into InAs therough Fe/InAs junction, and verified spin injection is possible with polarization of 【similar or equal】 4 % which is the first report with barrierless junction between ferromagnet and semiconductor and even one of the highest number reported by reliable experiments.