Defects in quasicrystals, revisited II- perfect and imperfect dislocations

TL;DR

This paper revisits the geometric properties of defects in quasicrystals, focusing on dislocation splitting, classification of phason defects, and the relative ease of climb versus glide, expanding understanding of defect structures.

Contribution

It introduces a natural splitting of disvection lines into perfect and imperfect dislocations and classifies phason defects based on their position relative to the acceptance window.

Findings

Disvection lines split into perfect and imperfect dislocations.

Phason defects classified by their position in the acceptance window.

Climb is generally easier than glide for dislocations.

Abstract

In this paper, the second part of a survey of the geometric properties of defects in quasicrystals studied from the Volterra viewpoint (see ref. [1]), we show that: 1$- $ a {\sf disvection line} L$_{||} \subset \mathrm E_{||}$ of Burgers vector $\textbf b =\textbf b_{||}+\textbf b_\bot $ splits naturally along L$_{||}$ into a {\sf perfect dislocation} of Burgers vector $\textbf b_{||}$ and an {\sf imperfect dislocation} of Burgers vector related to $\textbf b_{\bot}$, akin to a stacking fault, (a 'phason' defect), 2$- $ the 'phason' defects are classified according to the relative position of $\Sigma_{\bot}$ with respect to a partition of the acceptance window AW which depends on the direction of $\textbf b_\bot $. The perpendicular cut surface $\Sigma_{\bot}\subset \mathrm {AW}$ here introduced is a mapping of the usual cut surface $\Sigma_{||}\subset\mathrm E_{||}$. Imperfect dislocations in QCs are somewhat similar to Kronberg's synchroshear dislocations. It is also shown that climb must generically be easier than glide.