The effects of the dynamical Jahn-Teller interaction on the EPR of shallow acceptors in GaP

Abstract

Morgan (1) has shown that as a result of the dynamical Jahn-Teller interaction each of four components of the Γ8 valence band in a cubic semiconductor is mixed with other components by lattice distortions of symmetry E(Γ3) and T2(Γ5). The resultant vibronic state has the same symmetry as the unmixed state (gG8) but shows different paramagnetic behavior. The g values of the EPR spectrum depend on the strength of the dynamical Jahn-Teller interaction. The effective strength of the interaction can be varied by application of a uniaxial stress. We have carried out EPR measurements on single crystals of GaP doped with C, Zn and Cd acceptors and determined both the isotropic and anisotropic g values as functions of the applied uniaxial stress. Their variation is consistent with the theory of Morgan (1) when we assume that for the shallower acceptors C and Zn, the coupling is predominantly from lattice distortions of symmetry E(T3) whereas the comparatively deeper acceptor Cd is more strongly coupled to lattice distortions of T2(Γ5) symmetry. © 1972.