Electron Transport by a Transverse Acoustoelectric Stoneley Wave

The effect of acoustoelectric charge transport is associated with the possibility of amplifying acoustoelectric waves using an external electric field and has been studied in detail for body and surface waves. Electron transport by a transverse acoustoelectric wave (e.g., a Stoneley wave propagating along the heterojunction of two piezoelectric semiconductor layers) is considered in this work for the first time. Analytical expressions for the acoustic conductivity tensor components are derived that depend on the wave phase velocity and electron drift velocity in an external electric field. It is shown that the alternating acoustoelectric current is a sum of two surface currents: the drift current, which depends linearly on the external electric field, and the current that depends nonlinearly on this field. An expression for the acoustoelectric electron mobility is derived. It is found that the acoustoelectric current induced by an electron density wave grows infinitely when the electron drift velocity becomes equal to the wave phase velocity. The analytical expressions obtained for the mobility and current density can be used in calculating current–voltage characteristics of Stoneley wave acoustoelectric field-effect transistors.