ANISOTROPIC ELECTRON-TRANSPORT THROUGH A RECTANGULAR ANTIDOT LATTICE

Rectangular antidot lattices are prepared by Ga focused ion beam implantation with lateral periodicities in the range of 0.1-2.0-mu-m. For current flow along the long periodicity of the antidot lattice the carrier density determined from the slope of the classical Hall resistance rho(xy) is 30% larger than the carrier density deduced from the minima of the magnetoresistance oscillations. Furthermore the Hall plateaus are shifted to the low field side of the extrapolation of the classical Hall resistance. For current flow along the short periodicity a dramatic negative magnetoresistance is observed similar to a square antidot lattice. We conclude that the transport properties of the rectangular antidot lattices are dominated by the strongly modulated charge distribution in these systems.