It was shown that a non-zero vacuum energy density (Casimir energy) for a scalar field appeared in a continuous elastic solid, due to the presence of a screw dislocation. An exact expression was derived, for this energy density, in terms of the Burgers vector which described the defect; at zero and finite temperatures. This very simplified model for the solid (infinite, non-magnetic, one defect) already revealed a non-zero Casimir energy which could play a role in solid-state physics. For instance, its non-zero temperature part could contribute to the specific heat of solids. It was proposed that the model could be extended to magnetic materials. There were other possible classical effects of the defect, in that a point charge in the presence of a disclination suffered a self-force that was induced by the defect. An identical effect was to be expected in the dislocation case, and might give rise to bound states.

Casimir Effect around a Screw Dislocation. I.Pontual, F.Moraes: Philosophical Magazine A, 1998, 78[5], 1073-84