Weak localization in an ensemble of ballistic cavities filled with antidots arrays

Abstract

We present experimental data on the ballistic weak localisation in square cavities filled with antidot arrays. The weak localisation peak is cusp-like at mK temperatures and clearly deviates from a Lorentzian line shape, which is the theoretical prediction for a classical chaotic system. Although the ideal system, a Sinai billiard, is in principle purely chaotic, directly reflected, non-chaotic trajectories lead to the behaviour of a mixed system in experiment. We demonstrate this by detailed semiclassical analysis. In comparison, empty cavities of equal geometry show a sharper peak in the form of a Lorentzian. Here, imperfections of the experimental structure (boundary roughness, small- angle scattering) seem to change the dynamics of the nominally regular system to chaotic, contrary to the antidot case.