Dynamics of electrons in a 2D region coming from a point-contact

Ballistic and quasi-ballistic transport in mesoscopic systems is, nowadays, a fundamental tool for the investigation of electronic processes in semiconductors. In this work we present some results concerning a numerical simulation of electrons entering a 2D mesoscopic region from a point contact; a magnetic field is applied perpendicular to the structure and influences the electron dynamics. The simulation is performed through a numerical solution of the Schroedinger equation in a finite-difference scheme. It includes a magnetic field and an arbitrary potential V(r). In this way, the quantum effects of impurities on the conductance of the system have been analysed. The resul shows that each impurity configuration characterizes, in a particular way, the transport properties.