Dislocation Mobility and Anomalous Shear Modulus Effect in He-4 Crystals

Malmi-Kakkada, Abdul N and Valls, Oriol T and Dasgupta, Chandan (2017) Dislocation Mobility and Anomalous Shear Modulus Effect in He-4 Crystals. In: JOURNAL OF LOW TEMPERATURE PHYSICS, 186 (3-4). pp. 259-274.

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Abstract

We calculate the dislocation glide mobility in solid He within a model that assumes the existence of a superfluid field associated with dislocation lines. Prompted by the results of this mobility calculation, we study within this model the role that such a superfluid field may play in the motion of the dislocation line when a stress is applied to the crystal. To do this, we relate the damping of dislocation motion, calculated in the presence of the assumed superfluid field, to the shear modulus of the crystal. As the temperature increases, we find that a sharp drop in the shear modulus will occur at the temperature where the superfluid field disappears. We compare the drop in shear modulus of the crystal arising from the temperature dependence of the damping contribution due to the superfluid field, to the experimental observation of the same phenomena in solid He and find quantitative agreement. Our results indicate that such a superfluid field plays an important role in dislocation pinning in a clean solid He at low temperatures and in this regime may provide an alternative source for the unusual elastic phenomena observed in solid He.

Item Type:	Journal Article
Publication:	JOURNAL OF LOW TEMPERATURE PHYSICS
Additional Information:	Copy right for this article belongs to the SPRINGER/PLENUM PUBLISHERS, 233 SPRING ST, NEW YORK, NY 10013 USA
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	28 Feb 2017 10:12
Last Modified:	28 Feb 2017 10:12
URI:	http://eprints.iisc.ac.in/id/eprint/56279

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