Structure Of Atomic Chains Research Articles

VS4/NCDs nanowire as efficient cathode for aqueous rechargeable Zinc-ion batteries.

VS4 has emerged as a promising cathode material for aqueous zinc-ion batteries (ZIBs), attracting significant interest due to its unique layered atomic chain structure and high capacity. However, the low electrical conductivity of the material limits the diffusion rate of zinc ions, ultimately compromising its structural stability. In this study, we demonstrate the synthesis of nanorods through a simple hydrothermal recombination of carbon dots on vanadium sulfide. The distinctive layered structure of VS4, in conjunction with nitrogen-doped carbon dots (NCDs), increases the number of available active sites, thereby enhancing the conductivity of VS4/NCDs. VS4/NCDs cathode exhibits high specific capacity of 110 mAh g-1 at 5 A g-1 and superior rate performance in ZnSO4 electrolytes, significantly outperforming that of the layered VS4 cathode.

Synthesis of low-dimensional metal halide CsAgCl2 for X-ray scintillation applications

Low-dimensional metal halides, which possess efficient luminescent properties, have garnered significant interest in the fields of optoelectronics and radiation detection. This study introduces novel lead-free silver-based metal halide material, CsAgCl2 microcrystals (MCs). These MCs have a one-dimensional atomic chain structure and a unique [AgCl5]4- tetragonal shared triangular configuration. CsAgCl2 MCs exhibit excellent performance as X-ray scintillators due to their bright broadband yellow emission and fast decay time in the microsecond range. The large Stokes shift of 350 nm is produced by self-trapped exciton emission. In X-ray scintillation applications, CsAgCl2 MCs demonstrate a high light yield of 13280 photons/MeV and a wide range of linear scintillation response. It is noteworthy that the CsAgCl2 MCs maintain good stability under both atmospheric conditions and continuous X-ray irradiation. The sample was used in an X-ray imaging screen, which clearly presented the X-ray projection image of a wooden stick. As a result, this research not only contributes to the collection of lead-free metal halide scintillators but also indicates that CsAgCl2 MCs have a wide range of future applications and potential in areas such as medical imaging, scientific research, and diagnostic and detection technologies.

Computational study of conductance through Cu, Ag, Au and Pt atomic chain contacts

Atomic size wires are basic devices of molecular electronics and a common model for simulation of transport properties of other molecular devices, where hypothetical semi-infinite equidistant atomic chains are considered as electrodes. In this work, structure of infinite linear Cu, Ag, Au and Pt atomic chains was studied at nonrelativistic, scalar and spin–orbit zeroth order relativistic approximation levels. Bonds in chains were characterized within Quantum Theory of “Atoms In Molecules” approach. Conductance through finite chains of six atom length between bulk leads for bias voltage range of 0.0–1.0 V was calculated within non-equilibrium Green’s function approach combined with density functional theory. Chain conductance at high bias voltages correlates with product of Jenkins’ metallicity and positively defined kinetic energy density at bond critical points of corresponding infinite atomic chains. Variation of number of atoms in finite Au and Pt chains showed weak “odd-even” oscillations of chain conductance at some bias voltages.

Unveiling the structure of calcium borate glass by neutron diffraction, MAS-NMR, Raman and first-principles calculations

Calcium borate glass is a challenging system, due to the rich variety of borate units and alterable boron coordination number, and hence they are also of particular interest for academic study. In this study, neutron diffraction, solid-state magic angle spinning nuclear magnetic resonance (MAS-NMR) and Raman spectroscopy were combined with first-principles calculations, experience potential structure refinement (EPSR) simulations to investigate the structure of xCaO·(1-x)11B2O3 glass. Property data such as density and glass transition temperature were also measured to study the impact of structural changes on the properties of glasses. The structure of calcium borate glass was analyzed using various methods including structural unit, atomic pair bond length, coordination number, ring structure, chain structure and cavity distribution. Most notably, the atomic labeling method plays a key role in the structural analysis process. Through this method some new conclusions were obtained. For example, the increase of CaO content mainly leads to the conversion of BO to NBO in the glass structure, and has little effect on the content of BO3 and BØ4-. This result further leads to an increase in Ca-NBO interactions. Interestingly, the bond length distribution of Ca-NBO and B-NBO is shorter than that of Ca-BO and B-BO, so the glass structure becomes denser. The structural reason why the density of calcium borate glass is less than the crystal density was also revealed. This study contributes to unveiling the structure of calcium borate glass and exploring the correlation between the structure and properties of calcium borate glass, which provides a valuable reference for developing more valuable amorphous materials.

Efficient Synthesis of Highly Crystalline One-Dimensional CrCl3 Atomic Chains with a Spin Glass State.

One-dimensional (1D) magnetic material systems have attracted widespread interest from researchers because of their peculiar physical properties and potential applications in spintronics devices. However, the synthesis of 1D magnetic atomic chains has seldom been investigated. Here, we developed an iodine-assisted vacuum chemical vapor-phase transport (I-VCVT) method, utilizing single-walled carbon nanotubes (SWCNTs) with 1D cavities as templates, and high-quality and high-efficiency fabrication of 1D atomic chains of CrCl3 was achieved. Furthermore, the structure of CrCl3 atomic chains in the confined space of SWCNTs was analyzed in detail, and the charge transfer between the 1D atomic chains and SWCNTs was investigated through spectroscopic characterization. A comprehensive study of the dynamic magnetic properties revealed the existence of spin glass states and freezing of the 1D CrCl3 atomic chains at around 3 K, which has never been seen in bulk CrCl3. Our work established an effective strategy for the control synthesis of 1D magnetic atomic chains with promising potential applications in further magnetic-based spintronics devices.

Structure and Electronic State of Boron Atomic Chains on a Noble Metal (111) Surface

Structure and Electronic State of Boron Atomic Chains on a Noble Metal (111) Surface

Morphology‐Controllable Perovskite‐Like RbCu2Br3 Single Crystals with Strong Photoelectronic Anisotropy for UV Detection

AbstractThe carrier transport characteristics of grain boundary‐free, high‐purity metal halide single crystals make them ideal materials for photodetectors. However, the relationship between photoelectric properties and crystal morphology as well as electronic structure is not sufficiently explored. In this work, RbCu2Br3 single crystals with high quality and multiple morphologies are successfully prepared for the first time. Based on angle‐resolved polarized Raman spectroscopy and polarized photoluminescence, the anisotropy of the 1D atomic chain structure of these crystals is identified. Besides, according to the calculation of partial charge density (PCD), electron localization function (ELF), and carrier mobility related to deformation potential theory (DPT), it is found that RbCu2Br3 single crystals have formed a transport path located in [CuBr4] tetrahedral double chain from 1D electronic structure. It is also explored how the factors including electronic constraints, effective mass, mechanical properties, and deformation potential affect the mobility of crystal plane. Moreover, the device constructed on crystal {100} planes has shown great potential for UV detection. This work not only provides a theoretical basis for the performance regulation of RbCu2Br3 single crystals in experiments but also offers scientific guidance for the growth of single crystal materials with an asymmetric structure and for the application of anisotropy‐related optoelectronics.

A DFT study on transformation of TiN's atomic chain structure into atomic chain structures of HfN and ZrN

New spintronic, magnetic, magneto-optic, and biomedical applications call for two-dimensional magnetic materials with programmable electronic characteristics. Based on the fundamentals of density functional theory, the atomic chain structure of TiN in this study has been converted into the atomic chain structures of HfN and ZrN. The analysis of structural stability, density and projected density of states (DOS, PDOS), band structures, and magnetic behaviour of the proposed chain system configurations of Ti8-xZrxN8 and Ti8-xHfxN8 (where x belongs to {0–7}) has been done to observe the changes with respect to the existing bulk structures of TiN, ZrN, and HfN. The obtained results indicate that the systems under study possess an indirect band gap, higher conductivity, and consistent magnetic moment. These attributes of proposed atomic chain structures will certainly be useful for a variety of optoelectronic and biomedical applications.

Vanadium Tetrasulfide for Next-Generation Rechargeable Batteries: Advances and Challenges.

Alkali metal-ion batteries (SIBs and PIBs) and multivalent metal-ion batteries (ZIBs, MIBs, and AIBs), among the next-generation rechargeable batteries, are deemed appealing alternatives to lithium-ion batteries (LIBs) because of their cost competitiveness. Improving the electrochemical properties of electrode materials can greatly accelerate the pace of development in battery systems to cover the increasing demands of realistic applications. Vanadium tetrasulfide (VS4 ) is known as a prospective electrode material due to its unique one-dimensional atomic chain structure with a large chain spacing, weak interactions between adjacent chains, and high sulfur content. This review summarizes the synthetic strategies and recent advances of VS4 as cathodes/anodes for rechargeable batteries. Meanwhile, we describe the structural characteristics and electrochemical properties of VS4 . And we describe in detail its specific applications in batteries such as SIBs, PIBs, ZIBs, MIBs, and AIBs as well as modification strategies. Finally, the opportunities and challenges of VS4 in the domain of energy research are described.

One-dimensional excitons in long phosphorene atomic chains

The electronic structure of phosphorene atomic chains (PACs) embedded in various dielectric environments is studied theoretically by using a configuration interaction approach beyond the conventional double-excitation scheme. While the nominal single-particle gap of the PACs is shown to roughly obey an expected scaling law of ${L}^{\ensuremath{-}2}$, where $L$ measures the length of PACs, the quasiparticle shift is found to gradually converge to a value that is insensitive to the dielectric environment as $L$ increases. In the meantime, exciton binding energies are revealed to obey a simple scaling law of $0.96/(\ensuremath{\kappa}L)\ensuremath{-}0.02$, with $\ensuremath{\kappa}$ being the effective dielectric constant. As $L$ goes to infinity, the quasiparticle and excitonic effect are both found to be greatly suppressed as if the long-range electron-electron interactions are quenched in long PACs.

One-dimensional structures in nanoconfinement

Exploring the structure of low-dimensional materials is a key step towards a complete understanding of condensed matter. In recent years, owing to the fast developing of research tools, novel structures of many elements have been reported, revealing the possibility of new properties. Refining the investigation of one-dimensional atomic chain structures has thus received a great amount of attention in the field of condensed matter physics, materials science and chemistry. In this paper, we review the recent advances in the study of confined structures under nanometer environments. We mainly discuss the most interesting structures revealed and the experimental and theoretical methods adopted in these researches, and we also briefly discuss the properties related to the new structures. We particularly focus on elemental materials, which show the richness of one-dimensional structures in vacuum and in nanoconfinement. By understanding the binding and stability of various structures and their properties, we expect that one-dimensional materials should attract a broad range of interest in new materials discovery and new applications. Moreover, we reveal the challenges in accurate theoretical simulations of one-dimensional materials in nanoconfinement, and we provide an outlook of how to overcome such challenges in the future.

Effect of Substrate on Structural and Electronic Properties of Au-Pd, Au-Pt and Au-Ag Atomic Chains

We report structure and electronic properties of Au-Pd, Au-Pt and Au-Ag bimetallic atomic chains absorbed on NiAl(110) and Cu(110) substrate. It is found that the presence of substrate significantly influences the electronic structure of the chains. Atoms of single chains of Au-Pd, Au-Pt and Au-Ag bind more strongly with Ni atoms of NiAl substrate, as compared with Cu atoms in Cu(110). The interaction between chain atoms is found stronger than the chain-substrate atoms, when chains are placed on Cu substrate, while it is other way round in case of chains on NiAl substrate. Effect of change in positions of atoms in bimetallic chains in presence of substrate is studied by placing double chains of Au-Pd, Au-Pt and Au-Ag on Cu (110) substrate in three different configurations. It is found that Au-Pd and Au-Pt bimetallic chains stabilize in double zigzag topology, when placed on Cu (110) substrate. While Au-Ag chains exhibit ladder topology on Cu(110) substrate. Ferromagnetism that is observed in ground state of free standing chains of Au-Pd and Au-Pt is not found when chains are absorbed on NiAl(110) and Cu(110) substrate. It is likely that the interaction between chain and substrate atoms results to zero magnetic moment.

One-dimensional Rashba states in Pb atomic chains on a semiconductor surface

We investigate the electronic and spin structure of Pb atomic chains on a $\mathrm{Si}(100)\ensuremath{-}2\ifmmode\times\else\texttimes\fi{}1$ surface using first-principles calculations. We revealed that the electronic spectra of linear dimerized Pb chains with orientations perpendicular and parallel to the Si dimers are characterized by one-dimensional large Rashba spin splitting providing exclusive spin polarization of the carriers that makes these systems suitable for studying the spin-transport phenomena and realizing a tunable spin current. A buckled dimerized Pb chain with a parallel orientation was predicted to be an insulating Rashba system with a vortical spin texture and asymmetric charge distribution. In this paper we trace the origin of Rashba band anisotropy and its interplay with chain geometry. The Rashba parameters of the considered chains are compared with other well-known systems.

Cu Atomic Chain Supported on Graphene Nanoribbon for Effective Conversion of CO2 to Ethanol.

Cu catalysts are well-known for their good performance in CO2 conversion. Compared to CO and CH4 production, C2 products have higher volumetric energy densities and are more valuable in industrial applications. In this work, we screened the catalytic ability of C2 production on several 1D Cu atomic chain structures and find that Cu edge-decorated zigzag graphene nanoribbons (Cu-ZGNR) are capable of catalyzing CO2 conversion to ethanol, and CH3 CH2 OH is the main C2 product with a maximum free energy change of 0.60 eV. The planar tetracoordinate carbon structures in Cu-ZGNR provide unique chemical bonding features for catalytic reaction on the Cu atoms. Detailed mechanism analyses with transition states search show that CO* dimerization is favored against CHO* formation in the reaction. By adjusting the CO* coverage, the selectivity of the C2 product can be enhanced owing to less pronounced steric effects for COCHO*, which is feasible under experimental conditions. This study expands the catalyst family for C2 products from CO2 based on nano carbon structures with new features.

VS4 with a chain crystal structure used as an intercalation cathode for aqueous Zn-ion batteries

Vanadium tetrasulfide (VS4) with a beneficial one-dimensional atomic-chain structure is reported to be able to serve as a favorable intercalation cathode material for a high-performance Zn-ion battery.

Structure, stability and electronic properties of bimetallic atomic chains of Au–Ag and Au–Pt

Quantum confinement of electrons in atomic chains provides the most powerful and versatile means to control electronic, optical, magnetic and thermoelectric properties of materials needed to make diodes, spin valves and optical labels. Furthermore, the alloying of metallic atoms in different compositions produces novel mechanical, electronic and chemical behaviours in bimetallic chains as well as in other structures. This motivated us to perform theoretical investigations on the structure, stability, magnetic and electronic properties of bimetallic atomic chains of Au–Ag and Au–Pt, by using Vienna ab-initio simulation package (VASP), which is based on the density functional theory (DFT) within generalised gradient approximation. We have used tension and cohesive energy criteria to assess the stability of the Au–Ag and Au–Pt atomic chains. A comparison between the computed cohesive energies of various possible structures are made to suggest the most probable chain structures that can occur in break junction experiments. Our computed results suggest that the ground state of the Au–Ag and Au–Pt atomic chains should have zig-zag geometry. Furthermore, the most favoured chain structures that can be formed at the last stage of nanowires stretching are: (i) an atomic chain with alternate arrangement of equal number of Au and Ag / Pt atoms and (ii) an atomic chain where two Ag / Pt atoms are separated by one Au atom. Our results on the electronic band structure and optical properties suggest that the Au–Ag atomic chain could be of semiconducting nature, while the most stable Au–Pt chain is metallic in nature. A spin-polarised calculation with the inclusion of spin–orbit coupling shows that the Au–Pt atomic chains are magnetic, if the number of Au atoms is not more than the number of Pt atoms.

Hybrid Mg/Li-ion batteries enabled by Mg2+/Li+ co-intercalation in VS4 nanodendrites

Hybrid Mg2+/Li+ batteries (MLIBs) are very intriguing energy storage devices that combine the advantages of Li and Mg electrochemical redox processes. However, the battery performances of MLIBs in previous researches are usually restricted by the fact that only Li+ ions are participated in the reactions on the cathodes. We propose that this obstacle can be overcome by significantly improving the diffusion/transfer kinetics of highly-polarized divalent Mg2+ ions in the cathode material, so that both Mg2+ and Li+ can be intercalated into the cathode material. Herein, we demonstrate that the electrochemical energy storage capability of MLIBs can be greatly improved by employing vanadium tetrasulfide (VS4) nanodendrites as cathode material. Benefited from the special one-dimensional atomic-chain structure, the VS4 nanodendrites are capable for the simultaneous reversible insertion/extraction of both Mg2+ and Li+ ions with fast diffusion kinetics, high capacity and long cycling stability. The MLIBs assembled with VS4 nanodendrites cathodes exhibit a high reversible capacity of ∼300 mAh g−1 at 500 mA g−1, and a high cycle stability with the capacity maintained at 110 mAh g−1 after 1500 cycles at 1000 mA g−1.

Highly Branched VS4 Nanodendrites with 1D Atomic‐Chain Structure as a Promising Cathode Material for Long‐Cycling Magnesium Batteries

Rechargeable magnesium batteries have attracted increasing attention due to the high theoretical volumetric capacities, dendrite formation-free characteristic and low cost of Mg metal anodes. However, the development of magnesium batteries is seriously hindered by the lack of capable cathode materials with long cycling life and fast solid-state diffusion kinetics for highly-polarized divalent Mg2+ ions. Herein, vanadium tetrasulfide (VS4 ) with special one-dimensional atomic-chain structure is reported to be able to serve as a favorable cathode material for high-performance magnesium batteries. Through a surfactant-assisted solution-phase process, sea-urchin-like VS4 nanodendrites are controllably prepared. Benefiting from the chain-like crystalline structure of VS4 , the S22- dimers in the VS4 nanodendrites provide abundant sites for Mg2+ insertion. Moreover, the VS4 atomic-chains bonded by weak van der Waals forces are beneficial to the diffusion kinetics of Mg2+ ions inside the open channels of VS4 . Through a series of systematic ex situ characterizations and density functional theory calculations, the magnesiation/demagnesiation mechanism of VS4 are elucidated. The VS4 nanodendrites present remarkable performance for Mg2+ storage among existing cathode materials, exhibiting a remarkable initial discharge capacity of 251 mAh g-1 at 100 mA g-1 and an impressive long-term cyclability at large current density of 500 mA g-1 (74 mAh g-1 after 800 cycles).

Geometric stability and electronic structure of infinite and finite phosphorus atomic chains**Project supported by the National Natural Science Foundation of China (Gant Nos. 11274380, 91433103, 11622437, and 61674171), the Fundamental Research Funds for the Central Universities, China, and the Research Funds of Renmin University of China (Grant No. 16XNLQ01). Qiao was supported by the Outstanding Innovative Talents Cultivation Funded Programs

One-dimensional mono- or few-atomic chains were successfully fabricated in a variety of two-dimensional materials, like graphene, BN, and transition metal dichalcogenides, which exhibit striking transport and mechanical properties. However, atomic chains of black phosphorus (BP), an emerging electronic and optoelectronic material, is yet to be investigated. Here, we comprehensively considered the geometry stability of six categories of infinite BP atomic chains, transitions among them, and their electronic structures. These categories include mono- and dual-atomic linear, armchair, and zigzag chains. Each zigzag chain was found to be the most stable in each category with the same chain width. The mono-atomic zigzag chain was predicted as a Dirac semi-metal. In addition, we proposed prototype structures of suspended and supported finite atomic chains. It was found that the zigzag chain is, again, the most stable form and could be transferred from mono-atomic armchair chains. An orientation dependence was revealed for supported armchair chains that they prefer an angle of roughly 35°–37° perpendicular to the BP edge, corresponding to the [110] direction of the substrate BP sheet. These results may promote successive research on mono- or few-atomic chains of BP and other two-dimensional materials for unveiling their unexplored physical properties.

Thermal stability and spontaneous breakdown of free-standing metal nanowires

We present a model for vacancy-mediated spontaneous breakdown of free-standing monatomic nanowire based on exclusively random, thermally activated motion of atoms. The model suggests a new two-step vacancy-mediated mechanism for nanowire rupture compared to the more complex three-step hole-mediated mechanism driving the disintegration of nanowire on crystalline surface. It also demonstrates that a free-standing nanowire breaks down much more rapidly than a nanowire on a substrate, because it cannot experience the stabilizing effect of the nanowire/substrate interactions. The rupture mechanism includes single atomic vacancy generation, preceded by appearance of weakly bonded active atoms. The analysis of the simulation data indicates that the active atoms act as a precursor of vacancy formation. These two successive events in the temporal evolution of the nanowire morphology bring the free-standing nanowire into irreversible unstable state, leading to its total disintegration.The present study also manifests an unexpected substantial increase of the nanowire lifetime with diminishing the strength of the atomic interactions between the nanowire atoms. The simulation data reveal three energy regions where a large oscillatory variation of nanowire lifetime is realized. The first region of strong atomic interactions is characterized by tight nanowire rigidity and short lifetime. The next, second region in the consecutive step-down of the attractive interatomic force is characterized by generation of wave-shaped morphology of the atomic chain, enhanced flexibility and dramatic increase of nanowire lifetime. In the last, third region, further weakening of the interactions returns the nanowire again to unstable, short-lifetime state. The observed phenomenon is considered as a “stick-like” to “polymer-like” transition in the nanowire atomic structure as a result of interaction energy variation. The enhanced flexibility reduces the nanowire free energy since it favors and facilitates the rate of entropy propagation in the atomic chain structure. The observed phenomenon opens a way for a new type atomic scale control on the thermal stability of both free-standing nanowire and nanowire on crystalline substrate. The present study also extends the validity of the three-step breakdown mechanism of nanowire on crystalline substrate to the specific case of thermally activated free-standing nanowire rupture not affected by any external forces.