Magneto-optical effect of the Wannier exciton in a biaxial ZnP2 crystal. III

We have measured reflection and absorption spectra of ZnP 2 monoclinic crystal in different magnetic fields up to 40 T at 4.2 K. From anisotropic properties of the exciton structures it is suggested that a bottom of the conduction band and a top of the valence band consist of s -like and p z -like electrons, respectively. This suggestion is supported by anisotropy in paramagnetic splittings. Especially, a g -factor of 4.0 leads to a conclusion that an isotropic crystal field is much larger than a spin-orbit splitting for the valence electron. Moreover, the diamagnetic shifts of the n =1 exciton line in the different orientations of the magnetic fields are reported and compared to those of the n =2 line previously reported.