title: Giant plasticity of a quantum crystal.
abstract: When submitted to large stresses at high temperature, usual crystals may irreversibly deform. This phenomenon is known as plasticity and it is due to the motion of crystal defects such as dislocations. We have discovered that, in the absence of impurities and in the zero temperature limit, helium 4 crystals present a giant plasticity that is anisotropic and reversible. Direct measurements on oriented single crystals show that their resistance to shear nearly vanishes in one particular direction because dislocations glide freely parallel to the basal planes of the hexagonal structure. This plasticity disappears as soon as traces of helium 3 impurities bind to the dislocations or if their motion is damped by collisions with thermal phonons.
authors: Laboratoire de Physique Statistique de l'Ecole Normale Supérieure, associé au CNRS et aux Universités PM Curie and D Diderot, Paris, France.
authors: Ariel
authors: A
authors: Haziot
authors: Xavier
authors: X
authors: Rojas
authors: Andrew D
authors: AD
authors: Fefferman
authors: John R
authors: JR
authors: Beamish
authors: Sébastien
authors: S
authors: Balibar