Comment on "Model for an Exciton Mechanism of Superconductivity"

Abstract
The excitonic mechanism of superconductivity in a metal-semiconductor system is studied from the point of view of the complete electron-electron interaction. It is shown that recent calculations of an enhancement of the superconducting transition temperature by way of virtual excitons involves a double counting of these processes. Once this is taken into account the enhancement disappears. The local-field effects in the semiconductor are discussed but it is shown that the off-diagonal elements of the interaction are no help in recovering the enhanced superconductivity.