Magnetoresistance of Potassium

Abstract

The linear magnetoresistance of single-crystal specimens of potassium, which is observed far into the high-magnetic-field regime, is not in accord with generally accepted ideas concerning the bands structure of potassium. The linear dependence of resistivity on field is, however, in accord with a charge-density-wave model for the metal. The charge-density wave modifies the Fermi surface by introducing many energy gaps that slice the Fermi surface. These heterodyne gaps undergo progressive magnetic breakdown. The model predicts the largest magnetoresistance for crystals in which the magnetic field is oriented along the [100] or [111] directions, and the smallest effect for crystals in which H is oriented parallel to [110]; these predictions are in agreement with observation.