MAGNETOTRANSPORT PHENOMENA IN PERIODICALLY DELTA-DOPED STRUCTURES

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