COMPOSITE FERMIONS IN MAGNETIC FOCUSING AND COMMENSURABILITY EXPERIMENTS

The dynamics of composite fermions in the ballistic transport regime i n etched semiconductor nanostructures, imposed on a two-dimensional el ectron gas, has been investigated around half Landau level filling. Th e non-uniform electrostatic potential in the vicinity of soft wails in such etched nanostructures has a strong repercussion on the trajector ies described by the quasi-particles. A transverse magnetic focusing g eometry, comprised of an array of abutted square cavities, and antidot lattices, in conjunction with the persistent photoconductivity effect , have been used as test vehicules. These experiments corroborate that the motion of composite fermions is governed by quasi-classical dynam ics and that enhanced soft wall effects are a hallmark of these hybrid particles. (C) 1998 Elsevier Science B.V. All rights reserved.