Theory of the anisotropic magnetoresistance in copper

The motion of the guiding center of magnetic circulation generates a charge transport. The application of kinetic theory to the motion gives a modified Drude formula for the magnetoconductivity: σ=e2ncτ/M*σ=e2ncτ/M*, where M⁎ is the magnetotransport mass distinct from the cyclotron mass, nc the density of the conduction electrons, and ττ the relaxation time. The density nc depends on the applied magnetic field direction relative to copper's face-centered-cubic lattice, when the Fermi surface of copper is nonspherical with necks. The anisotropic magnetoresistance of copper is calculated with the assumption of the necks representing by spheres of radius a centered at the eight singular points on the ideal Fermi surface. A good fit with experiments is obtained.