Strain-mediated ion-ion interaction in rare-earth-doped solids

TL;DR

This paper reveals a strain-mediated ion-ion interaction in rare-earth-doped solids, which scales as 1/r^3 and impacts spectral diffusion, offering a new perspective on ion interactions in these materials.

Contribution

It introduces a macroscopic model demonstrating a previously overlooked strain-mediated ion-ion interaction in rare-earth-doped solids.

Findings

The strain-mediated interaction scales as 1/r^3.

This interaction is comparable in magnitude to electric and magnetic dipole interactions.

Reevaluation of spectral diffusion mechanisms in literature.

Abstract

It was recently shown that the optical excitation of rare-earth ions produces a local change of the host matrix shape, attributed to a change of the rare-earth ion's electronic orbital geometry. In this work we investigate the consequences of this piezo-orbital backaction and show from a macroscopic model how it yields a disregarded ion-ion interaction mediated by mechanical strain. This interaction scales as $1/r^3$, similarly to the other archetypal ion-ion interactions, namely electric and magnetic dipole-dipole interactions. We quantitatively assess and compare the magnitude of these three interactions from the angle of the instantaneous spectral diffusion mechanism, and reexamine the scientific literature in a range of rare-earth doped systems in the light of this generally underestimated contribution.