The classical two-dimensional problem of noninteracting electrons scattered by a static impurity potential in the presence of a magnetic field is investigated both analytically and numerically. A strong negative magnetoresistance exists in such a system, due to freely circling electrons, which are not taken into account by the Boltzmann-Drude approach. A parabolic magnetoresistance is found at low fields.

• Received 23 March 2001

DOI:https://doi.org/10.1103/PhysRevB.64.233321