Enhanced Soft Wall Effects for Composite Fermions in Magnetic Focusing and Commensurability Experiments

Abstract

The dynamics of composite fermions in the ballistic transport regime in etched semiconductor nanostructures, imposed on a two-dimensional electron gas, has been investigated around half Landau level filling. The non-uniform electrostatic potential in the vicinity of soft walls in such etched nanostructures has a strong repercussion on the trajectories described by the quasi-particles. A transverse magnetic focusing geometry, 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 dynamics and that enhanced soft wall effects are a hallmark of these hybrid particles.