Local stress and superfluid properties of solid Helium-4
Abstract
More than half a century ago Penrose asked: are the superfluid and solid state of matter mutually exclusive or do there exist "supersolid" materials where the atoms form a regular lattice and simultaneously flow without friction? Recent experiments provide evidence that supersolid behavior indeed exists in Helium-4 -- the most quantum material known in Nature. In this paper we show that large local strain in the vicinity of crystalline defects is the origin of supersolidity in Helium-4. Although ideal crystals of Helium-4 are not supersolid, the gap for vacancy creation closes when applying a moderate stress. While a homogeneous system simply becomes unstable at this point, the stressed core of crystalline defects (dislocations and grain boundaries) undergoes a radical transformation and can become superfluid.
Cite
@article{arxiv.0805.3713,
title = {Local stress and superfluid properties of solid Helium-4},
author = {L. Pollet and M. Boninsegni and A. B. Kuklov and N. V. Prokofev and B. V. Svistunov and M. Troyer},
journal= {arXiv preprint arXiv:0805.3713},
year = {2010}
}