Beating patterns in the oscillatory magnetoresistance originated from zero-field spin splitting in AlxGa1-xN/GaN heterostructures

Beating patterns in the oscillatory magnetoresistance in Al0.11Ga0.89N/GaN heterostructures with one subband occupation have been investigated by means of temperature dependent Shubnikov-de Haas measurements at low temperatures and high magnetic fields. The zero-field spin splitting effect is observed by excluding the magnetointersubband scattering effect. The obtained zero-field spin splitting energy is 2.5 meV, and the obtained spin-orbit coupling parameter is 2.2 x 10(-12) eV m. Despite the strong polarization-induced electric field in the heterostructures, the spin-orbit coupling parameter in AlxGa1-xN/GaN heterostructures is smaller than that in other heterostructures, such as InxGa1-xAs/InyAl1-yAs ones. This is due to the large effective mass of the two-dimensional electron gas and the large GaN energy band gap in AlxGa1-xN/GaN heterostructures. With an increase in magnetic field, the spin splitting energy becomes smaller. The zero-field effect is still the dominant mechanism in AlxGa1-xN/GaN heterostructures at a magnetic field as high as 4.4 T. (c) 2006 American Institute of Physics.