Magnetotransport investigation of spin-orbit interactions in high-mobility GaN/AlGaN heterostructures.

Spin-splitting in the conduction band of a two-dimensional electron gas (2DEG) in GaN/AlGaN single interface heterostructures with mobilities of $\sim $80.000cm$^{2}$/Vs is investigated utilizing low field magnetoconductivity measurements. The observation of a distinct anti-localization feature near zero magnetic field signals the presence of significant spin-orbit coupling. A spin-orbit coupling value in the Rashba formalism of 6x10$^{-13}$eV{\AA} is extracted. For a typical 2DEG density of $\sim $10$^{12}$cm$^{-2}$ this value of the coupling strength corresponds to a spin-splitting energy of 0.3meV at the Fermi edge. The observed value is unexpectedly high for a wide-bandgap semiconductor. This talk summarizes our studies of the carrier density, mobility, and temperature dependence of the magnetoresistance data.