Spin-orbit interaction in an In_0:53Ga_0:47As/In _0:7Ga_0:3As shallow two-dimensional electron gas located 5 nm below InP surface barrier

A two-dimensional electron gas (2DEG) formed near a semiconductor surface has an advantage for the injection and detection of electron spins to realize a spin field-effect transistor (spin FET). Here, we investigated the strength of spin-orbit interaction (SOI) in 26.5nm In_0:52Al_0:48As and AlAs surface layer/5 nm InP/7.5 nm In_0.53Ga_0:47As/10nm In_0.7Ga_0.3As 2DEGs. By the selective wet etching of In_0.52Al_0.48As and InP layers, we achieved a 5nm InP/In_0.53Ga_0.47As/In_0.7Ga_0.3As 2DEG with a carrier density of 1:06× 10¹² cm^-2. Magnetoconductance is measured to evaluate the strength of Rashba SOI by the quantum correction of the conductance in the ballistic regime developed by Golub. The Rashba SOI parameter α reaches 3:85× 10^-12 eV m, which yields a spin rotation angle of 2.34π within the elastic scattering length indicating a good candidate for the channel of a spin FET.