Zeeman Effect and Crystal-Field Splitting of Excitons Bound to Isoelectronic Bismuth in Gallium Phosphide

Abstract

Zeeman analysis of the no-phonon lines in the luminescence of excitons bound to Bi isoelectronic traps in GaP confirms the original assignment of the electronic states proposed by Trumbore et al. The electron is derived from the singlet valley-orbit state. We conclude that the effect of the repulsive potential of the Bi core for electrons on the ordering of these valley-orbit states is overwhelmed by other influences. The anisotropic hole $g$ factor is negative for the Bi bound exciton state, unlike the bound exciton states previously examined in GaP. We identify a previously unreported 0.28±0.02-meV splitting of the $B$ line in zero magnetic field with a crystal-field interaction which lifts the fivefold degeneracy of the $J=2\mathrm{}$ exciton state.