Asymptotic Expansion for Small Magnetic Fields of Acoustoelectric Attenuation in Nondegenerate Semiconductors

The semiclassical analysis of acoustoelectric effects involves an infinite sum S(c,x) = ic exp (−x) ∑
n=−∞
^=∞
(n + ic)
⁻¹
I
n
(x), in which both arguments c and x depend on the magnetic field B. Recently Lebwohl, Carlson, and Mosekilde have found an integral representation for this sum, through which now we identify S(c,x) as a generalized hypergeometric function. Moreover we derive an asymptotic series for S(c,x) in the limit of small B, whose coefficients, in a parameter z, involve the iterated integrals of the complementary error function.