Mechanism for the low-temperature alignment of distortions of the VGaTeAs complexes in n-type GaAs under uniaxial pressure

The polarization of the 1.18 eV photoluminescence band associated with the VGaTeAs complexes in n-GaAs was studied under polarized resonant excitation at various temperatures and uniaxial pressures. An analysis was made within a model of an initially trigonal complex which in the light-emitting state is subject to the Jahn-Teller distortion retaining the symmetry plane of the {110}-type. It is shown that i) the ground state of the complex is also subject to the distortion; ii) at temperatures below 130 K the processes of reorientation and alignment occur in the ground state and the distortion orientation is conserved at the subsequent transition to the light-emitting state.