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

Spin–orbit coupling is investigated by magneto-conductivity measurements in AlxGa1–xN/AlN/GaN heterostructures with a polarization-induced two-dimensional electron gas having a carrier density range from 0.8×1012 cm−2 to 10.6×1012 cm−2. The zero-field electron spin-splitting energies extracted from the weak antilocalization measurements are found to scale with the Fermi wavevector kF as View the MathML source with effective linear and cubic spin–orbit parameters of α=5.0±0.3×10−13 eV m3 and γ=1.6±0.6×10−31 eV m3, 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.