Interaction of surface acoustic waves with an array of quantum wires

We describe the interaction of surface acoustic waves with electrons in an array of quantum wires, patterned out of a two-dimensional electron gas. Two specific geometries are considered, in which the surface acoustic wave travels parallel, or perpendicular to the wires. Although we assume the electron wave functions in different wires do not overlap, the screening of the phonon potential by the electrons in the wire array is a collective phenomenon. It is shown that the surface acoustic wave absorption cannot be described via the ac conductivity in the usual manner. We derive an integral equation for the dielectric function of the electrons in the quantum wire system, and solve it in the random phase approximation and in the narrow wire approximation. Using the dielectric function we find the absorption and the change in velocity of the surface acoustic waves.