Extraordinary plastic deformation of ionic inorganic crystals based on dislocation quantum structures

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H03838
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 26:Materials engineering and related fields
• Research Institution: Nagoya University
• Principal Investigator: Matsunaga Katsuyuki 名古屋大学, 工学研究科, 教授 (20334310)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 転位 / 移動度 / 電子構造 / すべり変形

Outline of Final Research Achievements

In this study, first-principles calculations were performed for glide dislocations in ZnS and ZnTe, in order to reveal a physical origin of experimentally observed light-dependent plasticity. It was experimentally reported that glide dislocations in ZnS are dissociated into two partial dislocations with stacking faults in between. The present calculations revealed that glide partial dislocations in ZnS tend to have unreconstructed core structures in their ground state. However, atomic structures of the glide dislocations can be reconstructed in the presence of carriers. Since atomic reconstruction of dislocation cores leads to decreased dislocation mobilities, the glide dislocations in ZnS can be strongly restricted in their motion when ZnS is exposed to external visible lights. It was also found that ZnTe also exhibits the similar results.

Free Research Field

材料科学

Academic Significance and Societal Importance of the Research Achievements

セラミックスは、他の材料にない優れた物性を持つ材料であるが、その脆い機械的性質がさらなる応用を阻んできた。しかし最近の研究で、光の有無によって、機械的性質が劇的に変化する無機結晶が存在することが判明した。本研究では、その代表例である硫化亜鉛結晶を主たる対象とし研究を進めたところ、その現象の起源がすべり転位という格子欠陥の局所的な電子状態にあることを明らかにした。この知見を活かした、材料合成や加工方法への応用とそれに伴う新たな展開が期待できる。