The Origin of Photoplasticity in ZnS

Fuente: arXiv
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Auteurs principaux: Genlik, Sevim Polat, Myers, Roberto C., Ghazisaeidi, Maryam
Format: Preprint
Publié: 2024
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author Genlik, Sevim Polat
Myers, Roberto C.
Ghazisaeidi, Maryam
author_facet Genlik, Sevim Polat
Myers, Roberto C.
Ghazisaeidi, Maryam
contents ZnS is a brittle material but shows extraordinary plasticity during mechanical tests performed in complete darkness. This phenomenon is known as the photoplastic effect, whose underlying mechanisms have long been unclear. We study the impact of light, via photoexcited charge carriers, on the dislocation core structure and mobility using first-principles calculations. We calculate the core structure and the charge-dependent Peierls barriers of the glide set of Shockley partial dislocations in ZnS. Our findings reveal that locally charged dislocations capture excess carriers in the system, leading to core reconstructions that alter the Peierls barrier, resulting in higher barriers and lower mobility for these dislocations. This altered and asymmetric mobility, depending on dislocation character (edge or mixed) and local stoichiometry (Zn or S rich), is responsible for the brittle behavior of ZnS under light exposure and will be reversed in complete darkness.
format Preprint
id arxiv_https___arxiv_org_abs_2406_13044
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Origin of Photoplasticity in ZnS
Genlik, Sevim Polat
Myers, Roberto C.
Ghazisaeidi, Maryam
Materials Science
ZnS is a brittle material but shows extraordinary plasticity during mechanical tests performed in complete darkness. This phenomenon is known as the photoplastic effect, whose underlying mechanisms have long been unclear. We study the impact of light, via photoexcited charge carriers, on the dislocation core structure and mobility using first-principles calculations. We calculate the core structure and the charge-dependent Peierls barriers of the glide set of Shockley partial dislocations in ZnS. Our findings reveal that locally charged dislocations capture excess carriers in the system, leading to core reconstructions that alter the Peierls barrier, resulting in higher barriers and lower mobility for these dislocations. This altered and asymmetric mobility, depending on dislocation character (edge or mixed) and local stoichiometry (Zn or S rich), is responsible for the brittle behavior of ZnS under light exposure and will be reversed in complete darkness.
title The Origin of Photoplasticity in ZnS
topic Materials Science
url https://arxiv.org/abs/2406.13044