Magnetoreflectance study of interfaces in Cd1-xMnxTe/CdTe/Cd1-xMnxTe structures

摘要

Magneto-reflectivity spectra are studied to determine giant spin splitting (GSS) of the excitonic transitions in a set of quantum wells Cd$-1$MIN@x$/Mn$-x$/Te/CdTe/Cd$- 1$MIN@x$/Mn$-x$/Te of different widths. Paramagnetic enhancement of the excitonic state GSS in the quantum wells is observed. Corrections to the GSS in the quantum well due to both a) reduction of the number of nearest neighboring magnetic ions with strong antiferromagnetic coupling at the CdTe/Cd$-1$MIN@x$/Mn$-x$/Te interfaces and b) mixing of materials of CdTe and Cd$-1$MIN@x$/Te in the interface region are calculated. It is shown that relative role of the paramagnetic enhancement increases as the quantum well width rises. It is noted that paramagnetic enhancement results from the weakening of two factors of the antiferromagnetic Mn-Mn coupling in the semicmagnetic semiconductors which usually tend to decrease GSS. Those factors are excluding of the part of magnetic ions contribution to the magnetization due to the antiferromagnetic coupling and account for the effective temperature of the magnetic ion subsystem.