Mechanical behavior of solid helium: Elasticity, plasticity, and defects

Abstract

At low temperatures, atoms in classical crystals are localized at lattice sites and can be regarded as distinguishable particles rendering quantum statistics unimportant. In solid helium, however, this situation is different: helium's small mass and weak interatomic potentials allow the exchange of neighboring atoms and the emergence of statistics dominated by quantum effects. This review covers the concepts and properties of solid helium and how crystalline properties are affected by structure, defects, vacancies, and dislocations. Recent experimental results on plastic deformation give promise to a new understanding of the mechanical properties of quantum solids.