Measurement of linear and cubic spin-orbit coupling parameters in AlGaN/AlN/GaN heterostructures with a polarization-induced two-dimensional electron gas

摘要

Spin-orbit coupling is investigated by magneto-conductivity measurements in AlxGa1-xN/AIN/GaN heterostructures with a polarization-induced two-dimensional electron gas having a carrier density range from 0.8 x 10(12)cm(-2) to 10.6 x 10(12)cm(-2). The zero-field electron spin-splitting energies extracted from the weak antilocalization measurements are found to scale with the Fermi wavevector k(F) as 2(alpha k(F) + gamma k(F)(3)) with effective linear and cubic spin-orbit parameters of alpha = 5.0 +/- 0.3 x 10(-13) eV m(3) and gamma= 1.6 +/- 0.6x 10(-13) eV m(3), respectively. The cubic spin-orbit coupling parameter is purely due to the bulk inversion asymmetry of the wurtzite crystal and has not been previously measured for the GaN system. (C) 2007 Elsevier B.V. All rights reserved.