Weak anti-localization of the two-dimensional electron gas in modulation-doped AlxGa1-xN/GaN heterostructures with two subbands occupation

Weak anti-localization of the two-dimensional electron gas (2DEG) in a modulation-doped Al0.22Ga0.78N/GaN single heterostructure has been investigated through magnetoresistance measurements at low temperatures. The elastic scattering time tau(e), dephasing time tau(phi) and spin-orbit scattering time tau(so) at various temperatures are obtained. When the second subband in the triangular quantum well at the heterointerface is occupied by the 2DEG, the weak anti-localization is observed clearly, which is thought to be due to the strong spin-orbit effect induced by the intersubband scattering. The spin-orbit effect and the intersubband scattering become stronger with increasing temperature. (C) 2004 American Institute of Physics.