|Unique Domain Structure of Two-Dimensional alpha-Mo2C Superconducting Crystals|
|Liu, Zhibo; Xu, Chuan; Kang, Ning; Wang, Libin; Jiang, Yixiao; Du, Jiao; Liu, Ying; Ma, Xiu-Liang; Cheng, Hui-Ming; Ren, Wencai; Ma, XL; Ren, WC (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China.
|摘要||The properties of two-dimensional (2D) materials such as graphene and monolayer transition metal dichalcogenides are strongly influenced by domain boundaries. Ultrathin transition metal carbides are a class of newly emerging 2D materials that are superconducting and have many potential applications such as in electrochemical energy storage, catalysis, and thermoelectric energy conversion. However, little is known about their domain structure and the influence of domain boundaries on their properties. Here we use atomic-resolution scanning transmission electron microscopy combined with large-scale diffraction-filtered imaging to study the microstructure of chemical vapor deposited high-quality 2D alpha-Mo2C superconducting crystals of different regular shapes including triangles, rectangles, hexagons, octagons, nonagons, and dodecagons. The Mo atom sublattice in all these crystals has a uniform hexagonal closely packed arrangement without any boundaries. However, except for rectangular and octagonal crystals, the C atom sublattices are composed of three or six domains with rotational-symmetry and well-defined line-shaped domain boundaries because of the presence of three equivalent off-center directions of interstitial carbon atoms in Mo octahedra. We found that there is very small lattice shear strain across the domain boundary. In contrast to the single sharp transition observed in single-domain crystals, transport studies across domain boundaries show a broad resistive superconducting transition with two distinct transition processes due to the formation of localized phase slip events within the boundaries, indicating a significant influence of the boundary on 2D superconductivity. These findings provide new understandings on not only the microstructure of 2D transition metal carbides but also the intrinsic influence of domain boundaries on 2D superconductivity.|
; xu, chuan
; jiang, yixiao
; liu, ying
; ma, xiu-liang
; cheng, hui-ming
; ren, wencai] chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china
; [kang, ning
; wang, libin
; du, jiao] peking univ, key lab phys & chem nanodevices, beijing 100871, peoples r china
; [kang, ning
; wang, libin
; du, jiao] peking univ, dept elect, beijing 100871, peoples r china
; Science & Technology - Other Topics
; Materials Science
|资助者||National Science Foundation of China [51325205, 51290273, 51521091, 51172240, 11374019]; Chinese Academy of Sciences [KGZD-EW-303-1, KGZD-EW-T06]
|通讯作者||Ma, XL; Ren, WC (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China.|
Liu, Zhibo,Xu, Chuan,Kang, Ning,et al. Unique Domain Structure of Two-Dimensional alpha-Mo2C Superconducting Crystals[J]. NANO LETTERS,2016,16(7):4243-4250.
Liu, Zhibo.,Xu, Chuan.,Kang, Ning.,Wang, Libin.,Jiang, Yixiao.,...&Ren, WC .(2016).Unique Domain Structure of Two-Dimensional alpha-Mo2C Superconducting Crystals.NANO LETTERS,16(7),4243-4250.
Liu, Zhibo,et al."Unique Domain Structure of Two-Dimensional alpha-Mo2C Superconducting Crystals".NANO LETTERS 16.7(2016):4243-4250.