Assessing the amorphousness and periodicity of common domain boundaries in silica bilayers on Ru(0 0 0 1)

Abstract

Domain boundaries are hypothesized to play a role in the crystalline to amorphous transition. Here we examine domain boundary structures in comparison to crystalline and amorphous structures in bilayer silica grown on Ru(0 0 0 1). Atomically resolved scanning probe microscopy data of boundaries in crystalline bilayer films are analyzed to determine structural motifs. A rich variety of boundary structures including rotational, closed-loop, antiphase, and complex boundaries are identified. Repeating units with ring sizes of 558 and 57 form the two most common domain boundary types. Quantitative metrics are utilized to assess the structural composition and degree of order for the chemically equivalent crystalline, domain boundary, and amorphous structures. It is found that domain boundaries in the crystalline phase show similarities to the amorphous phase in their ring statistics and, in some cases, in terms of the observed ring neighborhoods. However, by assessing order and periodicity, domain boundaries are shown to be distinct from the glassy state. The role of the Ru(0 0 0 1) substrate in influencing grain boundary structure is also discussed.

Atomic structure of a metal-supported two-dimensional germania film

“…4(a) and 4(b) show the highly symmetric 48 boundary, which alternates linearly between four-and eight-membered rings. The same arrangement has been reported for domain boundary structures present in silica monolayer films on Mo(112) [33,34], silica bilayer films on Ru(0001) [35], and aluminosilicate ultrathin films on Ru(0001) [36].…”

“…4(c) and 4(d) is a combination of Stone-Wales defects [37] arranged linearly that are separated by a six-membered ring in the germania monolayer film structure. Comparable 5577 structural motifs have been found in domain boundaries as well as in isolated rectangular loop defects in silica monolayer films on Ru(0001) with a slightly different arrangement [31,35,38]. The most complex boundary structure for the germania monolayer film is the one shown in Figs.…”

From Crystalline to Amorphous Germania Bilayer Films at the Atomic Scale: Preparation and Characterization

“…[14] These observations are in line with the DFT results showing al ack of 6M Rs as discussed above.M oreover,t he most prevalent antiphase boundary in the crystalline silica BL is formed by al inear arrangement of (5,5,8) ring-combinations. [15] AD DO analysis [16] provides further insight into the observed phase change from crystalline to amorphous germania. Theleft-hand column in Figure 4shows again the ringnetwork from Figure 2, right column.…”

Periodic and fragment models based on the local correlation approach

“…The effectiveness of the HL/LL protocol (section 2.6), based on the embedding models of sections 2.2–2.4 and the role of screening is studied on the interaction between the phosphorene sheets in a phosphorene bilayer (Figure a) and adsorption of a water monolayer on 2D silica (Figure b). Both black phosphorus (Bachhuber et al, ; Bachhuber et al, ; Cascella, Lin, Tavernelli, & Rothlisberger, ; Castellanos‐Gomez, ; Kim, ; Kou, Chen, & Smith, ; Li et al, ; Li et al, ; Liu et al, ; Qiao, Kong, Hu, Yang, & Ji, ; Sansone et al, ; Schütz et al, ; Shulenburger et al, ; Tran, Soklaski, Liang, & Yang, ; Wu, Fu, Zhou, Yao, & Zeng, ; Yang et al, ) which is a small gap semiconductor, and 2D silica (Björkman et al, ; Burson, Büchner, Heyde, & Freund, ; Huang et al, ; Lichtenstein et al, ; Lichtenstein, Heyde, & Freund, ; Löffler et al, ; Schlexer, Pacchioni, Wlodarczyk, & Sauer, ; Tosoni, Civalleri, & Ugliengo, ; Yu et al, ), an insulator, are promising systems from the technological point of view and are extensively studied experimentally and theoretically.…”