Systematics of electron-hole liquid condensation from studies of silicon with varying uniaxial stress

Abstract

Detailed experimental results based on luminescence experiments are obtained for the ground states, the critical points, and the phase diagrams for electron-hole liquid condensation in unstressed Si and in Si with large uniaxial stresses along the [100], [110], and [111] directions, and they are shown to be in good agreement with the corresponding results from microscopic calculations also presented here. These results represent the most extensive and detailed study to date of the systematic dependences of the properties of electron-hole liquid on varying semiconductor band structure (i.e., on varying underlying energetics). The present results are used to provide the first quantitative experimental verification of scaling relations connecting the ground state and the critical properties of electron-hole liquid. Quantitative agreement is obtained with a set of scaling relations given recently by Reinecke and Ying, and systematic deviations from the predictions of earlier proposals are found. The experimental data are used to distinguish between two theoretical approaches for determining the critical point for the condensation. The values of the critical temperature are in good agreement with those obtained from a droplet fluctuation model of the condensation, but they are found to be systematically lower than those obtained from a uniform plasma model of the critical region.