SURFACE-MODE IN THE FRACTIONAL QUANTIZED HALL-EFFECT IN SUPERLATTICES

We have studied the surface collective excitations in the fractional quantized Hall effect using the single mode approximation for a semiinfinite layered electron gas. The model consists of a periodic array of two dimensional electron gas in which the dielectric mismatch is at z = 0 and the conducting layers are at z = delta + nd. The surface mode exists both, for wave lengths shorter than a critical value and for thickness delta of the overlayer shorter than a half of the period of the superlattice.