An example was presented of a generically forbidden phase transition in one dimensions during finite-temperature stress-induced and thermally-assisted roughening of a super-climbing dislocation in a Peierls potential. It was also argued that such roughening was responsible for the strong suppression of the super-flow through solid 4He in a narrow temperature range observed by Ray and Hallock (2010). The narrow dip observed in the super-flow rate was suggested to owe its origin to the stress-induced roughening effect of super-climbing dislocations. That is, biasing a superfluid dislocation network by means of a macroscopically small overpressure could induce strong suppression of the first sound along the superfluid cores. Such suppression was characterized by the periodicity of the dip in the flow rate, which might be used as a critical experimental test of the proposed scenario.

Stress-Induced Dislocation Roughening: a Phase Transition in One Dimension at Finite Temperature. D.Aleinikava, A.B.Kuklov: Physical Review Letters, 2011, 106[23], 235302