材料科学
位错
纤锌矿晶体结构
结晶学
Burgers向量
螺旋(腹足类)
纳米结构
纳米尺度
凝聚态物理
化学物理
纳米技术
六方晶系
复合材料
化学
物理
生物
生态学
蜗牛
作者
J. Narayan,Roger Narayan
出处
期刊:ACS omega
[American Chemical Society]
日期:2022-07-18
卷期号:7 (29): 25853-25859
被引量:3
标识
DOI:10.1021/acsomega.2c03501
摘要
Screw dislocations play a significant role in the growth of crystalline structures by providing a continuous source of surface steps which represent available sites for crystal growth. Here, we show that pure screw dislocations can become helical from the absorption of defects (e.g., vacancies) and develop an attractive interaction with another helical dislocation to form a double helix of screw dislocations. These single and double helices of screw dislocations can result in the formation of interesting nanostructures with large Eshelby twists. We have previously proposed the formation of a double helix of screw dislocations to explain large Eshelby twists in crystalline nanostructures (Mater. Res. Lett.2021, 9, 453-457). We now show direct evidence for the formation of a double helix during thermal annealing of screw dislocations. The large Burgers vectors associated with these dislocations are used to explain the presence of large Eshelby twists in PbSe and PbS (NaCl cubic structure) and InP and GeS (wurtzite hexagonal structure) nanowires. These single- and double-helix screw dislocations can also combine to create even larger super Burgers vectors. These large effective Burgers also unravel the mechanism for the formation of nanopipes and micropipes with hollow cores and nanotubes with Eshelby twists in technologically important materials such as SiC, GaN, and ZnO that are utilized in a variety of advanced solid-state devices.
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