Landau Level Spectrum in In$_{0.53}$Ga$_{0.47}$As/InP Heterostructures

We report on magnetotransport results from a high-quality Rashba two-dimensional electron gas (2DEG) formed in undoped In$_{0.53}$Ga$_{0.47}$As/InP heterostructures, which were MOCVD grown on (100) InP substrate. The 2DEG has a density of n$_{e}\sim $ 1.1 x 10$^{11}$/cm$^{2}$ and a mobility of $\mu \sim $ 2 x 10$^{5}$ cm$^{2}$/Vs at T = 300 mK, and with illumination from a light-emitting diode, the n$_{e}$ can be tuned to 1.5 x 10$^{11}$/cm$^{2}$. A systematic pattern in R$_{xx}$ and R$_{xy}$, corresponding to the opening and closing of the integer quantum Hall gaps, was observed as a function of n$_{e}$, as well as a function of tilt angle in tilted field experiments. We are interested in the possible observation of resonant spin Hall conductance in this system. Experimental data and a brief discussion will be presented. The work at Rice was supported by NSF DMR-0706634.