Dislocations in quasicrystals and their interaction with cluster-like obstacles

TL;DR

This paper investigates dislocation behavior in quasicrystals, focusing on phason walls and their interaction with atomic obstacles, revealing unique energy fluctuations and mobility mechanisms distinct from periodic crystals.

Contribution

It introduces a model for dislocation-phason wall interactions in quasicrystals and highlights the limitations of traditional energy-based models like Peierls-Nabarro.

Findings

Disregistry energy exhibits large atomic-scale fluctuations.

Dislocation mobility is governed by local atomic obstacles.

Traditional energy models are inadequate for quasicrystals.

Abstract

A dislocation moving through a quasicrystal is leaving in its wake a fault denoted phason wall. For a two-dimensional model quasicrystal the disregistry energy of this phason wall is studied to determine possible Burgers vectors of the quasicrystalline structure. Contrary to periodic crystals, the disregistry energy is an average quantity with large fluctuations on the atomic scale. Therefore the dislocation core structure and mobility cannot be linked to this quantity e.g. by a Peierls-Nabarro model. Atomistic simulations show that dislocation motion is controlled by local obstacles inherent to the atomic structure of the quasicrystal.