Three dimensional potential distribution and quantized acoustoelectric current for a Al0.3Ga0.7As/GaAs two-dimensional electron gas heterostructure

We present the numerical results for the electrostatic potential distribution in AlGaAs/GaAs heterostructure with double split gates on the surface. The results are obtained from the self-consistent solution of the three dimensional Schrodinger-Poisson equation. The dependence of the potential on the applied gate voltages is discussed in detail. We pay special attention to the potential distribution along the electron transport direction in quasi-one-dimensional channel. The potential barrier heights calculated in the closed-channel-regime agree well with our experiment. The calculations show that the potential barrier height as a function of gate voltage differs strongly in the open-channel regime and the closed-channel regime. On the other hand, we calculate the quantized acoustic current by using the potential barrier obtained from self-consistent solution rather than using the simple analytical model. The results show that the quantized plateau accuracy is about 10(-5)-10(-4) within the minimum slope of the current plateau. (c) 2009 American Institute of Physics. [DOI: 10.1063/1.3148263]