We study the orbital magnetism of 2D lattices with chaotic motion of electrons withing a primitive cell. Using the temperature diagrammatic technique we evaluate the averaged value and rms fluctuation of magnetic response in the diffusive regime withing the model of non-interacting electrons. The fluctuations of magnetic susceptibility turn out to be large and at low temperature can be of the order of $\chi_{ L} (k_{ F}l)^{ 3/2}$, where $k_{ F}$ is the Fermi wavevector, $l$ is the mean free path, and $\chi_{ L}$ is the Landau susceptibility. In the certain region of magnetic fields the paramagnetic contribution to the averaged response is field independent and larger than the absolute value of Landau response.
Categories: cond-mat