Skyrmions and composite fermions in the limit of vanishing Zeeman energy

We describe the properties of a strongly interacting two-dimensional (2D) e lectron gas in high magnetic fields whose properties can be described in te rms of the formation of composite fermions at fractional Landau level occup ancy. For a Landau level occupancy nu = 1 the excitations correspond to spi n waves for high g-factors and magnetic fields, but when the g-factor is re duced close to zero by the use of hydrostatic pressure there is strong evid ence for the formation of skyrmions. Studies of composite fermions in the l imit of vanishing Zeeman energy also suggest that skyrmionic excitations ca n occur for composite fermions.