Dipole-type local configuration instability and charge transfer control as a theoretical background of a new long-memory effect for germanium-related centres in α-quartz

Abstract

A theoretical background of a new long-memory effect detected by A. Leyderman, J.A. Weil, and P.S. Rao [1] in α-quartz with paramagnetic [GeO₄]⁻Li⁺ centres is developed. First, this is a first order local configuration instability (LCI) of dipole type which induces a resonance tunnel transition of active ions between two equilibrium configurations. Second, this is an operation by LCI of electronic charge transfer corresponding to reorientations of localized triad vibronic charge transfer excitons. The latter effect is connected with the Coulomb blockade of the electronic charge transfer and is accompanied by strong localization of the system. As a result, LCI induces metastable properties of [GeO₄]⁻Li⁺ centres with important memory effect. Here the conservation of non-equilibrium populations of different centre modification states and long lifetime of these centres arise.

Key Words:

• local configuration instability
• memory effect
• charge transfer, tunneling.