Electronic transport and spatial current patterns of 2D electronic system: A recursive Green’s function method study

摘要

Based on the scanned probe microscopes, the local current properties in a nanodevice can be clearly exposed. However, it is still a big challenge to experimentally observe the atomic scale varying current pattern. A numerical-aided method is therefore very important for getting the local current information in a microsystem. In this study, we show the nonequilibrium Green’s function method to calculate the transport properties of two-terminal devices. For applying this method to larger systems, a recursive procedure is present in detail. The correctness of this method is confirmed by calculating the transport properties of a clean 2DEG. The conductance steps in such a sample match the corresponding band structure very well. Then, we calculate the current patterns in quantum point contact under a saddle-point potential. Several current jets can be clearly spotted which correspond to transport channels in quantum point contact. Meanwhile, the interference streaks are spotted near the edges of the device due to the reflection of electrons at the edges.