QUANTUM MAGNETORESISTANCE

An explanation is proposed of the unusual magnetoresistance, linear in magnetic field and positive, observed recently in nonstoichiometric s ilver chalcogenides. The idea is based on thr assumption that these su bstances are basically gapless semiconductors with a linear energy spe ctrum. Most of the excess silver atoms form metallic clusters which an doping the remaining material to a very small carrier concentration, so that even in a magnetic field as low as 10 Oe, only one Landau band participates in the conductivity.