Commensurability Effects in Hexagonal Antidot Lattices with Large   Antidot Diameters
  The observation of a novel type of commensurability resonance in two-dimensional, hexagonal antidot lattices is reported. These resonances have a classical character and occur at magnetic fields above the resonance that corresponds to the cyclotron motion around a single antidot. The resonances are visible only for antidots with effective diameters larger than 50 % of the lattice constant. Simulations reveal that they originate from quasi-stable electron trajectories that bounce between three neighboring antidots. This interpretation is backed by the observation of large-period Aharonov-Bohm type oscillations at low temperatures. 
S. Meckler, T. Heinzel, A. Cavanna, G. Faini, U. Gennser, D. Mailly