TRANSPORT-PROPERTIES OF A TRIANGULAR ELECTRON BILLIARD

The transport properties of triangular electron billiards are investig ated. By comparison of experimental data with simulations, maxims of t he magnetoresistance are related to classical electron orbits. In orde r to qualitatively understand why specific electron trajectories give rise to commensurability effects, we analyse the stability of the traj ectories using chaos theory. Numerical calculations of the Liapunov ex ponent of different trajectories show that relatively stable electron trajectories lead to commensurability effects, while more unstable tra jectories are less important for the magnetoresistance. Further, we in vestigated the influence of the geometry of the electron billiard on t he symmetry of electric conduction. We find that the triangular billia rd has non-symmetric contributions to the conductance that are not pre sent in mirror-symmetric billiards. The dependences on voltage, temper ature and magnetic field indicate that this nonlinearity is associated with quantum-interference effects.