Non-alloy/alloy transitions in the Sn/Cu(001) system: An STM, LEED and DFT study

Machaín, P.; Gayone, J. E.; Fuhr, J. D.; Ascolani, H.

doi:10.1016/j.apsusc.2017.05.201

Cited by 5 publications

(14 citation statements)

References 25 publications

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“…After the evaporation, the sample was connected again to the cold finger. From previous experiments, 24 we estimated a maximum temperature drift of 50 K. The preparation temperatures in the STM chamber are thus evaluated as (T prep = T ST M + 50K), which should be regarded as an upper value.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…In our former study, we have shown that TPA on the 0.5ML-Sn/Cu(100) surface alloy aggregates into compact domains of protonated molecules that are in registry with the 3 √ surface reconstruction. 13 However, at coverages lower than ∼ 0.1ML , Sn atoms are randomly distributed on the top surface layer, 24 which implies that TPA cannot adopt the same self-assembly mechanism and morphology of the 3 √ 2 case. Figure 6 compares the self-assembly morphology of the TPA molecules on the 0.1ML-Sn/Cu(100) surface alloy with those observed on the bare Cu(100).…”

Section: Modification Of Tpa Self-assembly By Sn Surface Alloyingmentioning

confidence: 99%

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Ubiquitous deprotonation of terephthalic acid in the self-assembled phases on Cu(100)

Argañaraz

Cristina

Rodríguez

et al. 2018

Phys. Chem. Chem. Phys.

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We performed an exhaustive study of terephthalic acid (TPA) self-assembly on a Cu(100) surface, where first-layer molecules display two sequential phase transitions in the 200-400 K temperature range, corresponding to different stages of molecular deprotonation. We followed the chemical and structural changes by means of high-resolution X-ray photoelectron spectroscopy (XPS) and variable-temperature scanning tunneling microscopy (STM), which were interpreted on the basis of density functional theory (DFT) calculations and photoemission simulations. In order to reveal the spectroscopic contributions of the molecules in different states of deprotonation, we modified the substrate reactivity by deposition of a small amount of Sn, which hampers the deprotonation reaction. We found that the characteristic molecular ribbons of the TPA/Cu(100) α-phase at a low temperature contain a significant fraction of partially deprotonated molecules, in contrast to the expectation of a fully protonated phase, where the self-assembly was claimed to be simply driven by the intermolecular double hydrogen bonds [OHO]. On the basis of our simulations, we propose a model where the carboxylate groups of the partially deprotonated molecules form single hydrogen bonds with the carboxylic groups of the fully protonated molecules. Using real time XPS, we also monitored the kinetics of the deprotonation reaction. We show that the network of mixed single and double hydrogen bonds inhibits further deprotonation up to ∼270 K, whereas the isolated molecules display a much lower deprotonation barrier.

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Section: Experimental Methodsmentioning

confidence: 99%

Section: Modification Of Tpa Self-assembly By Sn Surface Alloyingmentioning

confidence: 99%

Ubiquitous deprotonation of terephthalic acid in the self-assembled phases on Cu(100)

Argañaraz

Cristina

Rodríguez

et al. 2018

Phys. Chem. Chem. Phys.

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“…The experimental setup and preparation conditions used here to obtain the Sn/Ag(111) surfaces at low temperatures are the same as those used in our previous study of the nonalloy/alloy transition of the Sn/Cu(001) system. 18 The protocol followed for the preparations of the Sn/ Ag(111) surfaces at low temperatures is the following: for cooling the substrate, the continuous-flow cryostat associated to scanning tunneling microscopy (STM) working with liquid N 2 was used. Temperatures were measured by using a Si diode that is located close to the sample on the clamp of the cold finger.…”

Section: ■ Experimental and Calculation Methodsmentioning

confidence: 99%

“…The dosing times were limited to 4 min at most, which implies that no more than a 7 min time out of the cooling system. This procedure implies that the sample temperature during the Sn depositions was in the range between 130 and 170 K. 18 Theoretical Models. The density functional theory (DFT) calculations have been carried out within the slab-supercell approach by using the Vienna ab initio simulation package (VASP).…”

Section: ■ Experimental and Calculation Methodsmentioning

confidence: 99%

Growth of Open Honeycomb-like Sn Structures on Ag(111) at Low Temperatures

2021

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We studied, with a combination of low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM) experiments and density functional theory (DFT) calculations, the growth of Sn deposited on the Ag(111) surface kept at low temperatures (<170 K). The LEED experiments show the formation of two phases, a (4 × 4) phase for coverage between 0.17 ML and 0.65 ML and a ( 7 7) ×R19°phase that appears at a coverage of ∼0.75 ML. High-resolution STM images for a coverage of 0.37 ML, corresponding to the first phase, show nearly planar islands presenting a local order with a (4 × 4) periodicity. The formed Sn overlayer presents close (triangles) and open honeycomb-like (pentagons and deformed hexagons) structures. DFT calculations show that Sn adatoms should have a high mobility even at low temperatures and that a characteristic of the Sn layer is the coexistence of Sn atoms with three and four neighbors.

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“…In addition to reserving or tuning the electronic properties of stanene, another critical issue is the preparation of large-scale and high-quality stanene films . Even though tin tends to form alloys with many metals, ,, including Cu, Ag, and Au, , these alloy-terminated surfaces can serve as the template to grow stanene, as we show below. Many elegant examples, such as the growth of antimonene on alloyed Cu 2 Sb and Ag 2 Sb, , the segregation growth of germanene through Ag layers on Ge(111), and the generation of planar silicene through Au thin films on Si(111), have demonstrated the critical role of surface alloys in the formation of 2D materials.…”

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confidence: 99%

Recent Advances in Tin: From Two-Dimensional Quantum Spin Hall Insulator to Bulk Dirac Semimetal

Yao

Jiang

et al. 2020

J. Phys. Chem. Lett.

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An atomic layer of tin in a buckled honeycomb lattice, termed stanene, is a promising large-gap two-dimensional topological insulator for realizing room-temperature quantum-spin-Hall effect and therefore has drawn tremendous interest in recent years. Because the electronic structures of Sn allotropes are sensitive to lattice strain, e.g. the semimetallic αphase of Sn can transform into a three-dimensional topological Dirac semimetal under compressive strain, recent experimental advances have demonstrated that stanene layers on different substrates can also host various electronic properties relating to in-plane strain, interfacial charge transfer, layer thickness, and so on. Thus, comprehensive understanding of the growth mechanism at the atomic scale is highly desirable for precise control of such tunable properties. Herein, the fundamental properties of stanene and α-Sn films, recent achievements in epitaxial growth, challenges in high-quality synthesis, and possible applications of stanene are discussed.

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Non-alloy/alloy transitions in the Sn/Cu(001) system: An STM, LEED and DFT study

Cited by 5 publications

References 25 publications

Ubiquitous deprotonation of terephthalic acid in the self-assembled phases on Cu(100)

Ubiquitous deprotonation of terephthalic acid in the self-assembled phases on Cu(100)

Growth of Open Honeycomb-like Sn Structures on Ag(111) at Low Temperatures

Recent Advances in Tin: From Two-Dimensional Quantum Spin Hall Insulator to Bulk Dirac Semimetal

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