Zusammenfassung

For low Fermi energies and large antidot diameters an antidot superlattice changes into a dot superlattice. A negative magnetoresistance (NMR) for low magnetic fields coexisting with a commensurability peak is observed in this transition regime. We reproduce these features for both classical and quantum-mechanical calculations in a model, which traces the NMR back to saddle points with varying heights between the antidots.