The symmetry, reorientation kinetics, and coupling of the ground-state energy to stress have been determined for the ${\mathrm{Si}}_{\mathrm{As}}$-H complex in GaAs from uniaxial stress data. The stress-induced frequency shifts of the H-stretching vibration at 2094.5 ${\mathrm{cm}}^{\mathrm{-}1}$ are consistent with trigonal symmetry for the defect. The application of stress at temperatures above 85 K gives rise to a preferential alignment of the defect. The reorientation of the complex is thermally activated with an activation energy of 0.26 eV. The uniaxial stress data are consistent with the hydrogen atom being on the trigonal axis between the Si acceptor and a nearest-neighbor gallium atom.

• Received 14 May 1993

DOI:https://doi.org/10.1103/PhysRevB.48.8751