Predicting Dislocations and Grain Boundaries in Two-Dimensional Metal-Disulfides from the First Principles

详细信息    查看全文

• 作者：Xiaolong Zou ; Yuanyue Liu ; Boris I. Yakobson
• 刊名：Nano Letters
• 出版年：2013
• 出版时间：January 9, 2013
• 年：2013
• 卷：13
• 期：1
• 页码：253-258
• 全文大小：385K
• 年卷期：v.13,no.1(January 9, 2013)
• ISSN：1530-6992

文摘

Guided by the principles of dislocation theory, we use the first-principles calculations to determine the structure and properties of dislocations and grain boundaries (GB) in single-layer transition metal disulfides MS₂ (M = Mo or W). In sharp contrast to other two-dimensional materials (truly planar graphene and h-BN), here the edge dislocations extend in third dimension, forming concave dreidel-shaped polyhedra. They include different number of homoelemental bonds and, by reacting with vacancies, interstitials, and atom substitutions, yield families of the derivative cores for each Burgers vector. The overall structures of GB are controlled by both local-chemical and far-field mechanical energies and display different combinations of dislocation cores. Further, we find two distinct electronic behaviors of GB. Typically, their localized deep-level states act as sinks for carriers but at large 60掳-tilt the GB become metallic. The analysis shows how the versatile GB in MS₂ (if carefully engineered) should enable new developments for electronic and opto-electronic applications.

Keywords:

Two-dimensional; transition metal disulfides; dislocation; grain boundary; first principles theory