COULOMB DRAG IN THE EXTREME QUANTUM LIMIT

Coulomb drag resulting from interlayer electron-electron scattering in double layer 2D electron systems in a high magnetic field has been me asured. Within the lowest Landau level the observed drag resistance ex ceeds its nero magnetic value by factors of typically 1000. At half-fi lling of the lowest Landau level in each layer (nu = 1/2) the data sug gest that our bilayer systems are much more strongly correlated than r ecent theoretical models based on perturbatively coupled composite fer mion metals. [S0031-9007(98)05365-4].