Spin splitting in modulation-doped AlGaN/GaN two-dimensional electron gas

Abstract

AlGaN/GaN heterostructure devices have recently been attracting much attention because of their potential for high-performance microwave applications. Therefore, the electronic properties of a two-dimensional electron gas (2DEG) in AlGaN/GaN heterostructures have recently been discussed. We studied the magnetoresistance oscillation of the 2DEG at 0.4 K for various backgate voltages, and observed multiple oscillations resulting from spin splitting. The magnetoresistance shows clear beating due to the superposition of three oscillations. The frequency interval between the first and second largest frequencies is proportional to the total electron concentration and the measured spin-orbit interaction parameter agrees with the theoretical one. Therefore, the first and second largest frequencies are found to correspond to spin splitting by the spin-orbit interaction.