Abstract
Twin boundary (TB) engineering has been widely applied to enhance the strength and plasticity of metals and alloys, but is rarely adopted in thermoelectric (TE) semiconductors. Our previous first-principles results showed that nanotwins can strengthen TE Indium Antimony (InSb) through In–Sb covalent bond rearrangement at the TBs. Herein, we further show that shear-induced deformation twinning enhances plasticity of InSb. We demonstrate this by employing large-scale molecular dynamics (MD) to follow the shear stress response of flawless single-crystal InSb along various slip systems. We observed that the maximum shear strain for the (111)[11bar 2] slip system can be up to 0.85 due to shear-induced deformation twinning. We attribute this deformation twinning to the “catching bond” involving breaking and re-formation of In–Sb bond in InSb. This finding opens up a strategy to increase the plasticity of TE InSb by deformation twinning, which is expected to be implemented in other isotypic III–V semiconductors with zinc blende structure.
Highlights
Indium Antimony (InSb) is found to be one of the most potential high-performance thermoelectric (TE) material in III–V semiconductors[1,2,3,4,5,6]
InSb is widely used as infrared detectors because of its narrow band gap (0.18 eV at 300 K) and the highest mobility among III–V semiconductors[7,8,9,10,11]
In order to investigate the mechanical properties of InSb under realistic conditions, we employed molecular dynamics (MD) simulations to examine shear stress response along various slip systems for flawless singlecrystal InSb
Summary
Indium Antimony (InSb) is found to be one of the most potential high-performance thermoelectric (TE) material in III–V semiconductors[1,2,3,4,5,6]. In order to investigate the mechanical properties of InSb under realistic conditions, we employed molecular dynamics (MD) simulations to examine shear stress response along various slip systems for flawless singlecrystal InSb. Interestingly, we found deformation twinning forms along the ð111Þ1⁄2112 slip system in InSb. Similar phenomena have been observed in other materials that deformation may improve plasticity with strain-induced dislocation[35,36]. By identifying the chemical bond change during twin nucleation, we explained how the shear load along the ð111Þ1⁄2112 direction induces the deformation twinning, yet retains structural integrity. By calculating the energy of slipping and twinning, we explained why deformation twinning, rather than slipping, is more plausible under shear loading along the ð111Þ1⁄2112 direction These findings help provide improved understanding of deformation twinning in enhancing the plasticity of semiconductor with zinc blende structure
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