Possible large zero-field spin-splittings in In xGa 1− xAs/In yA1 1− yAs ( x, y=0.75) heterojunctions

Abstract

Zero-field spin-splittings are estimated from low-temperature magnetoresistances in two-dimensional electron gas (2DEG) in In x Ga 1−x As/ In y A1 1−y As (x,y=0.75) van der Pauw, Hall-bar and quantum wire field effect transistor (QWR-FET) samples. Maximum spin–orbit coupling constant α zero of 78 (×10 −12 eVm) was obtained in the Hall bar sample with 〈−1 1 0〉 direction, which has a sheet electron density and a mobility at 1.5 K of 1.1×10 12/cm 2 and 5.54×10 5 cm 2/ Vs . In-plane anisotropies of mobility as well as of α zero are confirmed in QWR-FET samples with 〈1 1 0〉 and 〈1 1 0〉 directions. If those results are considered together with the fact that a part of α zero was able to be changed by the gate-voltage, interface effect contributing to the zero-field splitting might play an important role in this heterojunction.