NEGATIVE MAGNETORESISTANCE IN ANTIDOT LATTICES WITH SADDLE-POINTS

We have performed quantum-mechanical as well as classical magnetotrans port calculations for a lattice of antidots with additional barriers. Both approaches reproduce the experimentally observed well-known comme nsurability peaks simultaneously with a negative differential magnetor esistance. By comparing both calculations, we find that quantum interf erence leads to an enhancement of the latter effect because of the inc reased probability of closed paths due to the insertion of additional potential barriers. We analyze the influence of the strength of inelas tic scattering as well as increasing temperatures, i.e. energy averagi ng, in order to separate the classical and the quantum contributions. (C) 1998 Elsevier Science B.V. All rights reserved.