MAGNETIC FOCUSING OF COMPOSITE FERMIONS THROUGH ARRAYS OF CAVITIES

The magnetoresistance R(xx) was investigated in arrays of abutted squa re cavities with lengths L ranging from 500 nm to 1.2 mu m near fillin g factor nu = 1/2. Maxima in R(xx) occur for effective magnetic field values satisfying the magnetic focusing condition between the cavity s pacing and the cyclotron radius of composite fermions, also for the ef fective magnetic field direction when composite fermions are deflected in the direction opposite to that of electrons. The experimental data are compared with simulation results based on a quasiclassical dynami cs of composite fermions in soft potentials.