INTERNAL STRUCTURE OF THE NITROGEN BOUND EXCITON IN GaP.

It is shown that the nitrogen defect in GaP exhibits a triply degenerate internal structure in both the neutral and negatively charged states which is not explained by conventional theories of an 'isoelectronic' defect. This structure appears in the optical spectra by relaxing selection rules and introducing splittings under applied uniaxial stress. The anomalous experimental results, which were recognized only after being predicted theoretically from a model developed for oxygen in GaP, reemphasizes the need for a new look at the one-electron theory of deep defects in semiconductors.