Dielectric relaxation in a deuteron glass

Abstract

We obtain the dielectric susceptibility of a deuteron glass based on a mean-field analysis of an Ising model with random bond strengths and random fields using a system-plus-bath approach. The two Ising pseudospin states represents two equivalent sites that the deuteron can occupy. Relaxation is caused by the random jumps of the deuteron from one site to another. It is then reasonable to assume an Arrhenius form of relaxation, on which we find that our derived results are in good qualitative agreement with experimental measurements on recently studied prototypical deuteron glasses, namely, Rb_1-x(ND₄)_xD₂PO₄ and Rb_1-x(ND₄)_xD₂AsO₄, above the glass transition.