Weak antilocalization and zero-field electron spin splitting in   AlGaN/AlN/GaN heterostructures with a polarization induced two-dimensional   electron gas
  Spin-orbit coupling is studied using the quantum interference corrections to conductance in AlGaN/AlN/GaN two-dimensional electron systems where the carrier density is controlled by the persistent photoconductivity effect. All the samples studied exhibit a weak antilocalization feature with a spin-orbit field of around 1.8 mT. The zero-field electron spin splitting energies extracted from the weak antilocalization measurements are found to scale linearly with the Fermi wavevector with an effective linear spin-orbit coupling parameter 5.5x10^{-13} eV m. The spin-orbit times extracted from our measurements varied from 0.74 to 8.24 ps within the carrier density range of this experiment. 
C. Kurdak, N. Biyikli, U. Ozgur, H. Morkoc, V. I. Litvinov