Spin splitting in InGaSb/InAlSb 2DEG having high indium content

We formed a novel metamorphic InGaSb/InAlSb two-dimensional electron gas (2DEG) having high indium contents around 0.9 by molecular beam epitaxy (MBE), and investigated its spin splitting through magneto-resistance (MR) characteristics by using Hall-bar samples. We observed clear Shubnikov–de Haas (SdH) type MR oscillations with some peak splitting induced by the Zeeman-like spin splitting over B=1 T at 1.5 K. An estimated splitting energy, ΔE, was 9 meV at B=4 T for the Landau index, n=1. Moreover, we also observed no peak splitting, i.e. spin split vanishing around B=1 T. Additionally, we confirmed some SdH beat patterns due to the zero-field spin splitting less than B=1 T, and the splitting energy at B=0, ΔE0, was estimated to be 4–6 meV from the SdH fast Fourier transform (FFT) analysis. We successfully demonstrated well fitting curves for the Landau plots of SdH peaks across B=1 T, thus the Zeeman-like splitting, the spin split vanishing, and the beat patterns due to the zero-field splitting can be connected, smoothly. The fitting curves were obtained by assuming not the Rashba effect but the Dresselhaus effect on the (0 0 1) surface with the confinement. Therefore, it suggests that the zero-field spin splitting in the present InGaSb/InAlSb 2DEG originates from the Dresselhaus effect.