Ductile deformation mechanism in semiconductor α-Ag2S（α-Ag2S半导体的延展变形机制）
Guodong Li, Qi An, Sergey I. Morozov, Bo Duan, William A. Goddard III, Qingjie Zhang, Pengcheng Zhai & G. Jeffrey Snyder
npj Computational Materials 4:44 (2018)
doi:s41524-018-0100-0
Published online:13 August 2018
Abstract| Full Text | PDF OPEN
摘要:无机半导体α-Ag2S在室温下表现出类似金属的延展性，但产生这种高延展性的机理尚未得到充分研究。基于密度泛函理论模拟α-Ag2S的本征力学性质研究表明，其潜在的延展性机制归因于以下三个因素：（i）低理想剪切强度和压力作用下的多个滑移路径，（ii）α-Ag2S八边形框架易于滑动而不需要破坏Ag-S键，（iii）金属Ag-Ag键的形成抑制Ag-S框架滑移并将其有效地耦合。α-Ag2S中的易滑路径（或键合的原子易重排而不破坏化学键）为半导体材料的塑性变形机制提供了新视角，这将有利于设计和开发柔性半导体材料和电子器件。
Abstract:Inorganic semiconductor α-Ag2S exhibits a metal-like ductile behavior at room temperature, but the origin of this high ductility has not been fully explored yet. Based on density function theory simulations on the intrinsic mechanical properties of α-Ag2S, its underlying ductile mechanism is attributed to the following three factors: (i) the low ideal shear strength and multiple slip pathways under pressure, (ii) easy movement of Ag–S octagon framework without breaking Ag？S bonds, and (iii) a metallic Ag？Ag bond forms which suppresses the Ag–S frameworks from slipping and holds them together.The easy slip pathways (or easy rearrangement of atoms without breaking bonds) in α-Ag2S provide insight into the understanding of the plastic deformation mechanism of ductile semiconductor materials, which is beneficial for devising and developing flexible semiconductor materials and electronic devices.
Editorial Summary
Semiconductors: easy slip explains silver sulfide ductility（硫化银半导体：易滑性解释了延展性）
虽然半导体通常是脆性的，但立方硫化银（α-Ag2S）中的原子键却是柔性的，在室温下即具有延展性。来自武汉理工大学的李国栋博士及其美国和俄罗斯的合作者，采用密度泛函理论模拟，研究了压力下α-Ag2S中Ag-S之间的键稳定性。他们发现，沿特定方向的剪切变形，会扭曲α-Ag2S中由Ag-S键形成的八边形框架，同时它还会产生新的Ag-Ag键以进一步耦合Ag-S框架，使α-Ag2S在变形过程中保持结构稳定。他们还发现Ag2S沿着两个不同晶面具有低理想剪切强度，这促进了原子滑移，同时保持了原子框架的完整性。半导体延展性的原子尺度机制研究，将有助于我们更好地理解和设计柔性电子产品。
While semiconductors are usually brittle, the atomic bonds in cubic silver sulfide (α-Ag2S) are flexible, making it ductile at room temperature.Guodong Li from Wuhan University of Technology and colleagues in the USA and Russia used density function theory simulations to examine the bonds between silver and sulphur in α-Ag2S under pressure.They found that shear deformation along specific directions distorted the octagons formed by the Ag-S bonds, while it also created new Ag-Ag bonds to couple the Ag-S octagons, enabling α-Ag2S to retain its structure during deformation.They also found low ideal shear strength along two crystallographic planes, which promoted easy atomic slip while maintaining the integrity of the atomic framework.Research into the atomic origins of ductility in semiconductors may help us better understand and design flexible electronics.
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