MAGNETOTRANSPORT PHENOMENA IN PERIODICALLY DELTA-DOPED STRUCTURES

The low-temperature magnetotransport properties of delta-doped multilayers have been measured in magnetic fields up to 14 T. A set of three GaAs samples is presented with sheet-doping concentrations in the dilute metallic region and sheet distances varying between 17 nm (aspect ratio 1) and 100 nm (aspect ratio 0.14). Self-consistent calculations are used to determine the subband energies, the total density of states, and the spatial extension of electron densities in different subbands. Three transport phenomena are discussed: the classical magnetoresistance for a two-carrier system, the Shubnikov-de Haas oscillations, and the quantum Hall effect. Reduced sheet distance is found to decrease the number of occupied minibands. The miniband which is closest to the Fermi energy undergoes a transition to an anisotropic three-dimensional band with renormalized mass in the growth direction, which is a direct consequence of the periodic doping.