Stress induced dislocation roughening -- phase transition in 1d at finite temperature

TL;DR

This paper demonstrates a theoretically forbidden phase transition in one-dimensional systems at finite temperature, specifically stress-induced dislocation roughening, which may explain experimental observations of superflow suppression in solid helium-4.

Contribution

It provides a novel example of a phase transition in 1D at finite temperature and links it to experimental phenomena in solid helium-4.

Findings

Dislocation roughening occurs via a phase transition in 1D at finite temperature.

The roughening explains suppression of superflow in solid helium-4.

The transition is stress-induced and thermally assisted.

Abstract

We present an example of a generically forbidden phase transition in 1d at finite temperature -- stress induced and thermally assisted roughening of a superclimbing dislocation in a Peierls potential. We also argue that such roughening is behind the strong suppression of the superflow through solid \he4 in a narrow temperature range recently observed by Ray and Hallock (Phys.Rev. Lett. {\bf 105}, 145301 (2010)).