Self-Assembly of a Two-Component Hydrogen-Bonded Network: Comparison of the Two-Dimensional Structure Observed by Scanning Tunneling Microscopy and the Three-Dimensional Crystal Lattice

Single silicon islands have been produced on the Si(111)(7 × 7) surface by a scanning tunneling microscope (STM) tip. Thermal relaxation of the isolated islands is observed by temperature variable scanning tunneling microscopy with strong tip effects. The sizes of islands depend on time t with a functional form of (t0-t)α. It is found that α≃2/3 for single bilayer islands, and α≃1 for three-dimensional ones. During the decomposition of three-dimensional islands, step bunching of over-layers takes place, while the islands have certain facets, like a pyramid just after the creation. At the final stages of the three-dimensional island decompositions, two-dimensional ones with 5 × 5 structure always appear. We have found that characteristic 5 × 5 islands with a long lifetime are formed during relaxation, but the 7 × 7 islands have mostlt a short lifetime. Rotation of small islands is also observed during relaxation. We discuss the results in terms of two-dimensional vapor phase processes.

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Structures of the ZrZn22 family: suprapolyhedral nanoclusters, methods of self-assembly and superstructural ordering

Acta Crystallographica Section B Structural Science ◽

10.1107/s0108768109012828 ◽

2009 ◽

Vol 65 (3) ◽

pp. 300-307 ◽

Cited By ~ 36

Author(s):

G. D. Ilyushin ◽

V. A. Blatov

Keyword(s):

Crystal Structures ◽

Self Assembly ◽

Topological Analysis ◽

Three Dimensional ◽

Topological Type ◽

Point Symmetry ◽

Two Dimensional ◽

The Matrix ◽

Nanocluster Precursor ◽

Dimensional Crystal

A combinatorial topological analysis is carried out by means of the program package TOPOS4.0 [Blatov (2006), IUCr Comput. Commun. Newsl. 7, 4–38] and the matrix self-assembly is modeled for crystal structures of the ZrZn22 family (space group Fd\bar 3m, Pearson code cF184), including the compounds with superstructural ordering. A number of strict rules are proposed to model the crystal structures of intermetallics as a network of cluster precursors. According to these rules the self-assembly of the ZrZn22-like structures was considered within the hierarchical scheme: primary polyhedral cluster → zero-dimensional nanocluster precursor → one-dimensional primary chain → two-dimensional microlayer → three-dimensional microframework (three-dimensional supraprecursor). The suprapolyhedral cluster precursor AB 2 X 37 of diameter ∼ 12 Å and volume ∼ 350 Å3 consists of three polyhedra (one AX 16 of the \bar 43m point symmetry and two regular icosahedra BX 12 of the \bar 3m point symmetry); the packing of the clusters determines the translations in the resulting crystal structure. A novel topological type of the two-dimensional crystal-forming 4,4-coordinated binodal net AB 2, with the Schläfli symbols 3636 and 3366 for nodes A and B, is discovered. It is shown that the ZrZn22 superstructures are formed by substituting some atoms in the cluster precursors. Computer analysis of the CRYSTMET and ICSD databases shows that the cluster AB 2 X 37 occurs in 111 intermetallics belonging to 28 structure types.

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ON THE ROLE OF KINKS AND STRAIN IN HETEROEPITAXIAL GROWTH: AN STM STUDY

Surface Review and Letters ◽

10.1142/s0218625x00000750 ◽

2000 ◽

Vol 07 (05n06) ◽

pp. 673-677

Author(s):

E. LUNDGREN ◽

M. SCHMID ◽

G. LEONARDELLI ◽

A. HAMMERSCHMID ◽

B. STANKA ◽

...

Keyword(s):

Diffusion Process ◽

Scanning Tunneling Microscopy ◽

Three Dimensional ◽

Growth Mode ◽

Scanning Tunneling ◽

Two Dimensional ◽

Heteroepitaxial Growth ◽

Tunneling Microscopy ◽

Exchange Diffusion

Interlayer diffusion of Co over steps of vacancy islands on the Pt(111) surface as studied by scanning tunneling microscopy is presented. It is demonstrated that Co atoms descend Pt steps by an exchange diffusion process at the step edge with the Pt atoms. Further, the exchange diffusion process is observed to occur at the corners (kinks) of the vacancy islands. The importance of kinks concerning whether the growth mode of a heteropitaxial film is two-dimensional or three-dimensional is demonstrated for the case of thin Co films on Pt(111). We argue that the strain in the Co film is to a large extent responsible for the kink formation.

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Scanning Tunneling Microscopy Study of α,ω-Dihexylsexithiophene Adlayers on Au(111): A Chiral Separation Induced by a Surface

Microscopy and Microanalysis ◽

10.1017/s1431927612000566 ◽

2012 ◽

Vol 18 (4) ◽

pp. 885-891 ◽

Cited By ~ 1

Author(s):

Yonghai Song ◽

Yu Wang ◽

Lingli Wan ◽

Shuhong Ye ◽

Haoqing Hou ◽

...

Keyword(s):

Scanning Tunneling Microscopy ◽

Self Assembly ◽

Room Temperature ◽

Three Dimensional ◽

Microscopy Study ◽

Molecular Structures ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Left Handed ◽

Bulk Structure

AbstractThe self-assembly of α,ω-dihexylsexithiophene molecules on an Au(111) surface was examined by using scanning tunneling microscopy at room temperature, revealing the internal molecular structures of the sexithiophene backbones and the hexyl side chains. The α,ω-dihexylsexithiophene formed a large and well-ordered monolayer in which the molecule lay flatly on the Au(111) surface and was separated into two chiral domains. A detailed observation reveals that the admolecules were packed in one lamellae with their molecular axis aligned along the main axis of the Au(111) substrate with their hexyl chains deviated from ⟨110⟩ direction of the Au(111) substrate by 12 ± 0.5°. In contrast to the behavior in the three-dimensional bulk structure, flat-lying adsorption introduced molecular chirality: right- and left-handed molecules separate into domains of two different orientations, which are mirror symmetric with respect to the ⟨121⟩ direction of the Au(111) substrate. Details of the adlayer structure and the chiral self-assembly were discussed here.

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Realizing Two-Dimensional Spin Arrays on Surfaces via Halogen-Bonding Molecular Self-Assembly

10.26434/chemrxiv.14738892.v1 ◽

2021 ◽

Author(s):

Dingguan Wang ◽

Zishen Wang ◽

Shaofei Wu ◽

Arramel Arramel ◽

Xinmao Yin ◽

...

Keyword(s):

Single Molecule ◽

Self Assembly ◽

Halogen Bonding ◽

Scanning Tunneling ◽

Two Dimensional ◽

Halogen Bonds ◽

Tunneling Microscopy ◽

Single Molecule Level ◽

Magnetic Devices ◽

Temperature Scanning

Well-ordered spin arrays are highly desirable for next-generation molecule-based magnetic devices, and yet its synthetic method remains a challenging task. Herein, we demonstrate the realization of two-dimensional supramolecular spin arrays on surfaces via halogen-bonding molecular self-assembly. A bromine-terminal perchlorotriphenymethyl radical with net carbon spin was synthesized and deposited on Au(111) to achieve two-dimensional supramolecular spin arrays. By taking advantage of the diversity of halogen bonds, five supramolecular spin arrays are presented with ultrahigh spin densities (up to the value of 3 × 10<sup>13</sup> spins at the size of a flash drive), as probed by low-temperature scanning tunneling microscopy at the single-molecule level. First principle calculations verify that the formation of three distinct types of halogen bonds can be used to tailor supramolecular phases via molecular coverage and annealing temperature. Our work demonstrates supramolecular self-assembly as a promising method to engineering 2D spin arrays for potential application in magnetic devices.

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