Dislocation Mobility in a Quantum Crystal: the Case of Solid 4He

TL;DR

This study explores the structure and movement of dislocations in solid helium-4, revealing dissociation tendencies and the importance of lattice resistance, which may influence the material's macroscopic properties.

Contribution

It provides the first detailed characterization of dislocation core structures and mobility mechanisms in solid 4He, highlighting the role of lattice resistance.

Findings

Dislocations tend to dissociate into partials on the basal plane.

Intrinsic lattice resistance significantly affects dislocation mobility.

Results offer insights into the link between dislocation behavior and macroscopic properties of 4He.

Abstract

We investigate the structure and mobility of dislocations in hcp 4He crystals. In addition to fully characterizing the five elastic constants of this system, we obtain direct insight into dislocation core structures on the basal plane, which demonstrates a tendency toward dissociation into partial dislocations. Moreover, our results suggest that intrinsic lattice resistance is an essential factor in the mobility of these dislocations. This insight sheds new light on the possible correlation between dislocation mobility and the observed macroscopic behavior of crystalline 4He.