Electrostriction in the semiconductor-to-metal transition of liquid Se-Te alloys

Publisher Website
Google Scholar
Abstract
The decrease in atomic volume which accompanies the electronic changes in the semiconductor-metal transition is explained by local compression of the dielectric fluid in the vicinity of negative ions, caused by the attractive force of the electric field on the polarizable atoms. A thermodynamic expression is derived which relates the atomic volume to the mean-square electric field in terms of the macroscopic polarizability and compressibility. The error due to the use of macroscopic parameters on an atomic scale of distance is found to be corrected by a term containing a single empirically determined parameter. This makes it possible to calculate volume changes from experimentally determined negative-ion concentrations which agree with experiment. Near the beginning of the semiconductor-metal transition, where it cannot be inferred from electronic data, information about the negative-ion concentrations is derived from the experimental volume contraction by the use of the model. The semiconductor-metal transition is caused by rapid thermal generation of negative ions, and we trace this to the strong electronic screening of the negative ions by holes, which occurs when the Fermi energy shifts into the valence band.