Charge-transfer effect in II–VI semimagnetic semiconductors Cd 1− xFe xTe and Cd 1− xFe xSe

Abstract

Fine-structure splittings (FSS) of the ground state of Fe 2+ ions in II–VI semimagnetic semiconductors (SMSC) CdTe and CdSe are obtained by a molecular-orbital approach. The theoretical FSS are in good agreement with experiment, and significant charge-transfer effects are found to be present in these systems. Using the present FSS, the Zeeman energy levels and the magnetization are studied as functions of the magnetic field B in the range 0–40 tesla applied in the directions [111], [110] and [100] for CdTe:Fe 2+ and in directions parallel and perpendicular to the crystal c-axis for CdSe:Fe 2+. The theoretical results reveal some energy level crossings and related magnetic anisotropy in SMSC, especially in high magnetic fields. The agreement between the currently revealed magnetic anisotropy and the experimental results again shows charge-transfer effects in Cd 1− x Fe x Te and Cd 1− x Fe x Se.