Magnetoresistance analysis of two-dimensional hole gases in GaN/AlGaN/GaN double heterostructures

Abstract

Magnetoresistance (MR) of two-dimensional hole gas (2DHG) samples fabricated from GaN/AlxGa1-xN/GaN (x = 0.2–0.25) double heterostructures has been investigated to reveal subband electronic parameters and low field spin splitting properties. In sample with high sheet hole density (ps ≤ 1.3 × 1013/cm2), 2DHG occupies two subbands, while in samples with low ps (≤0.3 × 1013/cm2), only one subband is occupied. In both samples, the low-field spin–orbit coupling constant α of 2DHG was obtained independently from the weak anti-localization data and the fast Fourier transform analysis of MR oscillations. The results yield a constant α ∼ 0.53–6.1 × 10−12 eVm and a spin splitting ΔE = 2αkf ∼ 0.6–6.0 meV. These results strongly depend on the hole mass value, but appear to be of the same order as the results for 2D electron gas in similar material systems and structures.