Theory of electronic transport of sound packets in metals in parallel magnetic field
Abstract
A theory is constructed for the propagation of sound pulses in metals in a magnetic field parallel to the wave front. Under the conditions of strong spatial dispersion kl≫ kR≫ 1 (k is the sound wave vector, l is the electron mean free path, and R is the cyclotron radius), because of deformation interaction with electrons in the metal a sound wave in pure samples gives rise to a system of spikes at distances which are multiples of 2R and move synchronously with the sound wave at the speed of sound. It is shown that the spike amplitudes are proportional to the squared local values of the deformation interaction potential Λ(p) and that their attenuation is determined by the averaged value of the potential. Attention is drawn to the possibility of establishing the form of Λ(p) by comparing theoretical and experimental results. The salient features of the formation of spikes are analyzed for an arbitrary electron dispersion relation.