Change in the energy of Jahn-Teller configurations of vacancy-donor complexes induced by uniaxial strain

Estimates are obtained for the energy splitting of equivalent Jahn-Teller c onfigurations of the light-absorbing state of < vacancy Ga (V-Ga)>-< tellur ium (Te-As)> complexes in n-GaAs generated by uniaxial stress along the dir ections [111] and [001]. These estimates are based on measuring the stress dependence of the polarization of photoluminescence associated with these c omplexes at T similar or equal to 2 and 77 K. A phenomenological model of t he complexes, which describes how the donor (Te-As) and the Jahn-Teller eff ect modify the initial t(2)-orbitals of the vacancy component of the comple x, is discussed as the effect of uniaxial strain. This model makes it possi ble to relate measured values of the energy splitting of equivalent configu rations relative to the splitting of the original t(2)-state of the vacancy arising from the presence of the donor and the Jahn-Teller effect. Compari son of calculations with experimental data shows that the contribution of t he Jahn-Teller effect to the formation of the light-absorbing state of the complex VGaTeAs exceeds the contribution due to the donor effect, although the two effects are comparable. (C) 1999 American Institute of Physics. [S1 063-7826(99)01011-X].