Abstract
We have measured the stress dependence of the indirect exciton spectrum of silicon at 77°K, for static uniaxial compression along the [111], [001], and [110] directions with light polarized parallel and perpendicular to the stress direction, using wavelength modulation. The high stresses reached in this work ( dyn ) have enabled us to accurately study the behavior of the valence-band maxima and the conduction-band minima under stress. The stress splitting of the valence bands is produced by (i) the orbital-strain interaction, which is described by two deformation potentials and , and (ii) the stress-dependent spin-orbit interaction, described by and . We find that eV, eV, eV, and eV. The same measurements yield a value for the shear deformation potential of the conduction-band minimum eV. The effect of hydrostatic deformation is interpreted in terms of two deformation potentials: (orbital-strain interaction) and (stress-dependent spin-orbit interaction). We obtain eV and . The hydrostatic coefficient of the indirect gap obtained from agrees with hydrostatic pressure measurements. In addition the stress-induced coupling between minima and the neighboring conduction band, described by the deformation potential eV, has been observed. Interpretation of the stress dependence of the intensities on the basis of one ( or ) or two ( and ) intermediate states gives the first conclusive evidence of a contribution of virtual transitions to the indirect adsorption edge of this material.
- Received 1 May 1970
DOI:https://doi.org/10.1103/PhysRevB.3.2623
©1971 American Physical Society