npj: 硫化银半导体变形机制——易滑性带来延展性

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虽然无机半导体通常是脆性的，但立方硫化银α-Ag2S在室温下却能表现出类似金属的延展性，只是造成这种高延展性的机理目前还不完全清楚。

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，采用密度泛函理论对α-Ag₂S的本征力学性质进行模拟，从原子尺度研究了压力作用下α-Ag₂S中Ag-S键的变形机理。他们发现，α-Ag₂S延展性机制由三个因素构成：（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。

该文近期发表于npj Computational Materialsv 4:44 (2018)，英文标题与摘要如下，点击左下角“阅读原文”可以自由获取论文PDF。

Ductile deformation mechanism in semiconductor α-Ag₂S 

Guodong Li, Qi An, Sergey I. Morozov, Bo Duan, William A. Goddard III, Qingjie Zhang, Pengcheng Zhai & G. Jeffrey Snyder 

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.

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