The Plastic Origin of van der Waals material GaGeTe

TL;DR

This paper reports the discovery of ultra high plasticity in GaGeTe, a germanium-based chalcogenide, due to bond engineering that prevents brittleness and enables large strain without fracture, promising for flexible electronics.

Contribution

It introduces GaGeTe as a highly plastic inorganic semiconductor and elucidates its atomic-scale mechanisms, highlighting bond engineering as a novel approach.

Findings

GaGeTe sustains up to 7.5% strain without fracture

Plasticity arises from interlayer gliding and lattice distortion

Bond engineering prevents brittleness in germanium chalcogenides

Abstract

Plastic inorganic semiconductors are promising candidates for high performance stable flexible electronics. Germanium based chalcogenide materials are well known for excellent semiconducting properties, specifically superior carrier mobility. However, these materials typically exhibit inherent brittleness, which in germanium tellurides originates from the intrinsic half bond nature of the metavalent Ge Te bond. Here, we report an ultra high plasticity germanium based chalcogenide of GaGeTe. Bulk GaGeTe can sustain a large engineering strain up to 7.5% without fracture. Through a comprehensive multi scale investigation ranging from macroscopic characterization to atomic resolution scanning transmission electron microscopy, we reveal that the exceptional plasticity is due to a synergistic effect of interlayer gliding and intralayer lattice distortion. DFT calculations further elucidate the chemical origin. The existence of Ga atoms avoids the formation of brittle metavalent Ge Te bonds. Instead, a robust honeycomb lattice formed by strong Ga Te, Ge Ge, and Ga Ge bonds preserves high bond strength under large tensile strains in simulations, thereby underpinning the macroscopic plastic behavior. This systematic study on the origin of the plasticity in GaGeTe introduces bond engineering as a potential approach for constructing plastic inorganic semiconductors.