Formation mechanism of twin domain boundary in 2D materials: The case for WTe2

• Published in: Nano research Vol. 12; no. 3; pp. 569 - 573
• Main Authors: Wang, Guan-Yong, Xie, Weiyu, Xu, Dan, Ma, Hai-Yang, Yang, Hao, Lu, Hong, Sun, Hao-Hua, Li, Yao-Yi, Jia, Shuang, Fu, Liang, Zhang, Shengbai, Jia, Jin-Feng
• Format: Journal Article
• Language: English
• Published: Beijing Tsinghua University Press 01.03.2019; Springer Nature B.V
• Subjects: Atomic/Molecular Structure and Spectra; Biomedicine; Biotechnology; Chemistry and Materials Science; Condensed Matter Physics; Density functional theory; Domains; Elasticity; Indium; Materials Science; Microscopy; Nanotechnology; Research Article; Scanning tunneling microscopy; Shear strain; Short term memory; Silicon substrates; Single crystals; Strain; Two dimensional materials; strain; WTe; twin domain boundary; scanning tunneling microscopy (STM); density functional theory
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-018-2255-x

Our scanning tunneling microscopy (STM) study observes, for the first time, twin domain boundary (TDB) formations on the surface of WTe 2 single crystal, which is glued by solidifying indium to Si substrate. In these TDB regions, a large inhomogeneous strain field, especially a critical shear strain of about 7%, is observed by geometric phase analysis. This observation does not obey the old believe that a small mechanical stress is sufficient to drive thermally-induced TDB formations in two-dimensional materials. To resolve the contradiction, we perform density functional theory calculations combined with elasticity theory analysis, which show that TDBs on WTe2 are entirely displacement-induced, for which a critical strain is necessary to overcome the onset barrier.