Nonreciprocal surface-acoustic-wave propagation in aluminum

Abstract

Nonreciprocal effects in surface-acoustic-wave (SAW) velocities for single-crystal aluminum have been observed at low temperatures in the presence of a magnetic field. They are of the order of 0.1% in the relative velocity change. This effect is due to coupling of the SAW displacement field to the conduction electrons moving on cyclotron orbits. We give a quantitative explanation for this effect.