Potential-dependent electron and holegvalues and quenched diamagnetism in GaP. II. Application of the theory of free and bound holes in a magnetic field to the pseudoacceptors (D0,X)

Abstract

The linear and quadratic Zeeman effect of three different ($D^0,X$) bound-exciton complexes in GaP with $D^0=\mathrm{S}, \mathrm{Se}, \mathrm{Te}$ is discussed in this paper. The binding energy of the hole in the complexes is estimated to be between zero (free hole) and the value of the effective-mass acceptor. We interpret therefore the linear Zeeman effect of these bound excitons in terms of an acceptor model with negative central-cell correction. The Zeeman effect of the two limiting cases is explicitly calculated and the experimental values are found to lie indeed in between the theoretical values, showing the correct dependence on the potential. We show theoretically that increased localization quenches the isotropic hole $g$ value $\tilde{k}$ in agreement with experimental data in the preceding paper. A general explanation of the sign of the isotropic Zeeman effect of bound holes in cubic III-V semiconductors and Ge, in terms of the anisotropy of the band structure of these materials is given. The increase of the anisotropic hole $g$ value $q$ with binding energy can be explained by an increase of the electron-phonon coupling of the hole to $E$ modes. The diamagnetic splitting of the ($D^0,X$) complexes which is reported for the first time for this type of system is one order of magnitude smaller than theoretically expected. This can be explained with a neutral-current model, which accounts for the correlation between electrons and holes.