Harnessing dislocation motion using an electric field

TL;DR

This paper demonstrates the control of dislocation motion in crystalline zinc sulfide using an external electric field, revealing charge-dependent behavior and opening new avenues for non-mechanical manipulation of material properties.

Contribution

It provides the first real-time evidence of electric field-driven dislocation motion in a crystal, elucidating charge effects on dislocation dynamics and barriers.

Findings

30° partial dislocations move with electric field direction

90° partial dislocations remain stationary under electric field

Charged dislocation cores have lower glide barriers, facilitating motion

Abstract

Dislocations, line defects in crystalline materials, play an essential role in the mechanical[1,2], electrical[3], optical[4], thermal[5], and phase transition[6] properties of these materials. Dislocation motion, an important mechanism underlying crystal plasticity, is critical for the hardening, processing, and application of a wide range of structural and functional materials[1,7,8]. For decades, the movement of dislocations has been widely observed in crystalline solids under mechanical loading[9-11]. However, the goal of manipulating dislocation motion via a non-mechanical field alone remains elusive. Here, we present real-time observations of dislocation motion controlled solely by an external electric field in single-crystalline zinc sulfide (ZnS). We find that 30{\deg} partial dislocations can move back and forth depending on the direction of the electric field, while 90{\deg} partial dislocations are motionless. We reveal the nonstoichiometric nature of dislocation cores using atomistic imaging and determine their charge characteristics by density functional theory calculations. The glide barriers of charged 30{\deg} partial dislocations, which are lower than those of 90{\deg} partial dislocations, further decrease under an electric field, explaining the experimental observations. This study provides direct evidence of dislocation dynamics under a non-mechanical stimulus and opens up the possibility of modulating dislocation-related properties.