Phonon-assisted tunneling in Jahn-Teller E$ \times $e impurity centers in crystals

Abstract

Tunnel transitions between various distorted states of impurity centers in crystals with the E$ \times $e Jahn-Teller effect are considered, taking into account changes in the dynamics of phonons caused by this effect. Both linear and quadratic vibrational interactions are taken into account. It was found that phonon scattering accompanying tunneling leads not only to a broadening of the energy spectrum of the transitions, but also to a deterioration in resonance. The results obtained are consistent with measurements of ultrasonic attenuation in Al2O3:Ni, GaAs:Mn and in GaAs:Cu doped crystals. A notable feature of E$ \times $e tunneling is the existence of a range of values for quadratic vibration interaction, in which the tunneling remains coherent at sufficiently high temperatures.