Acoustoelectric gain in magnetic fields

The acoustoelectric attenuation in nondegenerate semiconductors in a magnetic field is usually expressed as an infinite sum of modified Bessel functions. We transform this sum into an exact integral expression. From this expression we derive a simple approximation that is valid at small magnetic field strengths B and coincides with the zero magnetic field attenuation, calculated independently, if we allow B to approach zero. This integral expression has an essential singularity at B = 0; therefore the small magnetic field behavior cannot be described by a power series expansion in B. © 1972 The American Institute of Physics.