Résumé
We report on an optical manifestation of dynamic nuclear-spin polarization in optical pumping of p-InP. The electron-spin orientation is measured via the circular polarization degree of the luminescence. Depolarization by a transverse magnetic field (Hanle effect) yields the values of the electron lifetime and spin relaxation time. Dynamic nuclear polarization manifests itself when longitudinal and transverse magnetic fields are applied simultaneously. Optically induced nuclear magnetic fields up to 680 G are observed. All the experimental polarization curves can be well explained if one assumes that the nuclear polarization depends on the total external magnetic field. A qualitative explanation of this unexpected result is proposed. [S0163-1829(98)03707-2].