MAGNETOOPTICS NEAR THE L-POINT OF THE BRILLOUIN-ZONE IN SEMIMAGNETIC SEMICONDUCTORS

A group-theoretical analysis is used to express the Zeeman splittings of interband optical transitions at a critical point or L in terms of band-electronMn-d-electron exchange interaction values at that k. The +-to-- overall splitting of the E1 transition (4,5v6c) is shown to be, in general, equal but opposite to that of the spin-orbit-related E1+1 transition (6v6c), in agreement with recent experiments in Hg1-xMnxTe. The k dependence of the exchange interaction is discussed within a simple model. The splitting of E1 thus estimated is about 2.5 times larger in Hg1-xMnxTe than in Cd1-xMnxTe or Zn1-xMnxTe alloys; this explains the observed chemical variation. © 1990 The American Physical Society.