Weak antilocalization and zero-field electron spin splitting in Al_xGa_(1-x)N/AlN/GaN heterostructures with a polarization-induced two-dimensional electron gas

摘要

Spin-orbit coupling is studied using the quantum interference corrections to conductance in Al_xGa_(1-x)N/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 wave vector (E_(SS)=2αk_f) with an effective linear spin-orbit coupling parameter α=5.5 X 10~(-13) eVm. The spin-orbit times extracted from our measurements varied from 0.74 to 8.24 ps within the carrier density range of this experiment.