Borophene Nanoribbons Research Articles

Unlocking the potential of borophene nanoribbons for efficient hydrogen storage

This research explores the structural, electronic, optical, and hydrogen storage properties of borophene nanoribbons (BNRs) with armchair (ANR-B-H) and zigzag (ZNR B-H) edges. Computational simulations optimized these structures, revealing that 7ZNR-B-H has a superior binding energy. Chemical modifications, such as fluorine passivation and functionalization, influenced bond parameters and quantum properties. Bilayer BNRs showed increased stability and enhanced electrical conductivity. Our study demonstrated promising hydrogen storage capabilities, with passivated and functionalized BNRs achieving suitable adsorption energies and a significant gravimetric storage capacity of 20.32 wt%, exceeding DOE standards. NH2 functionalization notably improved adsorption energy, enhancing potential for efficient hydrogen storage. Changes in absorption spectra post-H2 adsorption further highlight BNRs’ potential for hydrogen storage applications. These findings provide valuable insights into BNRs, paving the way for their use in electronic devices and hydrogen storage systems.

Formation of Supernarrow Borophene Nanoribbons

AbstractBorophenes have sparked considerable interest owing to their fascinating physical characteristics and diverse polymorphism. However, borophene nanoribbons (BNRs) with widths less than 2 nm have not been achieved. Herein, we report the experimental realization of supernarrow BNRs. Combining scanning tunneling microscopy imaging with density functional theory modeling and ab initio molecular dynamics simulations, we demonstrate that, under the applied growth conditions, boron atoms can penetrate the outermost layer of Au(111) and form BNRs composed of a pair of zigzag (2,2) boron rows. The BNRs have a width self‐contained to ∼1 nm and dipoles at the edges to keep them separated. They are embedded in the outermost Au layer and shielded on top by the evacuated Au atoms, free of the need for post‐passivation. Scanning tunneling spectroscopy reveals distinct edge states, primarily attributed to the localized spin at the BNRs’ zigzag edges. This work adds a new member to the boron material family and introduces a new physical feature to borophenes.

Formation of Supernarrow Borophene Nanoribbons.

Borophenes have sparked considerable interest owing to their fascinating physical characteristics and diverse polymorphism. However, borophene nanoribbons (BNRs) with widths less than 2 nm have not been achieved. Herein, we report the experimental realization of supernarrow BNRs. Combining scanning tunneling microscopy imaging with density functional theory modeling and ab initio molecular dynamics simulations, we demonstrate that, under the applied growth conditions, boron atoms can penetrate the outermost layer of Au(111) and form BNRs composed of a pair of zigzag (2,2) boron rows. The BNRs have a width self-contained to ∼1 nm and dipoles at the edges to keep them separated. They are embedded in the outermost Au layer and shielded on top by the evacuated Au atoms, free of the need for post-passivation. Scanning tunneling spectroscopy reveals distinct edge states, primarily attributed to the localized spin at the BNRs' zigzag edges. This work adds a new member to the boron material family and introduces a new physical feature to borophenes.

Contact effects on electron transport along disordered borophene nanoribbons with line defects

Contact effects on electron transport along disordered borophene nanoribbons with line defects

Gas Molecules Adsorption on β₁₂ Borophene Nanoribbons and Nanosheets for the Gas Sensor Applications

Gas Molecules Adsorption on <i>β₁₂</i> Borophene Nanoribbons and Nanosheets for the Gas Sensor Applications

8-Pmmn borophene: edge states in competition with Landau levels and local vacancy states.

The tight-binding method is used to investigate the electronic and magnetic properties of borophene nano-ribbons (BNRs) in the presence of a perpendicular magnetic field. Most BNRs exhibit metallic characteristics due to edge bands. Additionally, the appearance of Landau levels (LLs) is strongly influenced by the edge states, contrasting with the sheet platform which produces distinct LLs. We also investigated single atomic vacancy disorders in BNRs and observed localized vacancy states (LVSs) resulting from atomic disorder. Both LVSs and LLs are influenced by the edge states, underscoring that the electronic and magnetic properties of BNRs are strongly edge-dependent. This aspect is crucial for consideration in experimental, theoretical, and computational studies.

Ultrafast switching in spin field-effect transistors based on borophene nanoribbons.

Borophene, owing to the high mobility and long spin coherent length of its carriers, presents significant opportunities in ultrafast spintronics. In this research, we investigate the spin-dependent conductance of a Datta-Das field-effect transistor (FET) based on an armchair β12-borophene nanoribbon (BNR) using the tight-binding (TB) Hamiltonian in combination with the non-equilibrium Green's function (NEGF) method. The spin FET electrodes are magnetized by ferromagnetic (FM) insulators arranged in both parallel and anti-parallel configurations. This device acts as a controllable spin filter in the presence of Rashba spin-orbit coupling (SOC) for both configurations and its spin current is well modulated by a gate voltage and the strength of the Rashba SOC. For anti-parallel configurations, an energy gap emerges within a certain range of incoming electron energy which can disappear for electrons with flipped spin under the Rashba SOC. Furthermore, our findings indicate that the electron-electron (e-e) interaction helps the spin precession of electrons injected into the spin FET channel, thereby strengthening the Rashba SOC effect. Notably, a gate voltage can adjust the current-voltage (I-V) characteristics of this device. Finally, our calculations demonstrate that under the same conditions, the current magnitude and Ion/Ioff ratio of borophene spin FETs are several times higher than those of graphene and silicene spin FETs.

Synthesis of Quantum-Confined Borophene Nanoribbons.

Borophene nanoribbons (BNRs) are one-dimensional strips of atomically thin boron expected to exhibit quantum-confined electronic properties that are not present in extended two-dimensional borophene. While the parent material borophene has been experimentally shown to possess anisotropic metallicity and diverse polymorphic structures, the atomically precise synthesis of nanometer-wide BNRs has not yet been achieved. Here, we demonstrate the synthesis of multiple BNR polymorphs with well-defined edge configurations within the nanometer-scale terraces of vicinal Ag(977). Through atomic-scale imaging, spectroscopy, and first-principles calculations, the synthesized BNR polymorphs are characterized and found to possess distinct edge structures and electronic properties. For single-phase BNRs, v1/6-BNRs and v1/5-BNRs adopt reconstructed armchair edges and sawtooth edges, respectively. In addition, the electronic properties of single-phase v1/6-BNRs and v1/5-BNRs are dominated by Friedel oscillations and striped moiré patterns, respectively. On the other hand, mixed-phase BNRs possess quantum-confined states with increasing nodes in the electronic density of states at elevated biases. Overall, the high degree of polymorphism and diverse edge topologies in borophene nanoribbons provide a rich quantum platform for studying one-dimensional electronic states.

Unidirectional reflectionless propagation in borophene plasmonic metamaterials

We propose a nonreciprocal borophene metamaterial consisting of a longitudinally separated array of double-layer borophene nanoribbons (BNRs) suspended in the air, exhibiting the unidirectional reflectionless properties at exceptional points (EPs) in the near-infrared communication band. Based on the coupled mode theory and the transfer matrix method, the transmission characteristics of light in the proposed structure can be effectively described. The internal loss and radioactive loss factors of the plasmonic system are successfully calculated by employing the theoretical model we proposed. Thus we conduct the analytical description of the unidirectional reflectionless phenomenon between two borophene plasmonic resonators, where the analytical results show excellent consistency with the finite-difference time-domain simulations. Different from the waveguide structure, the proposed structure has better adjustability that the regulation of EPs can be dynamically achieved by manipulating carrier density and the spatial separation between double-layer of BNRs. Our research results possess the possibility for promising application in tunable nanoelectronic devices in the communication band.

Refined degree bond partitions, topological indices, graph entropies and machine-generated boron NMR spectral patterns of borophene nanoribbons

The advent of borophene sheets and their nanoribbons has inspired significant experimental and theoretical research on the 2D-sheets and nanoribbons of boron, wonder materials of the future with the potential to replace graphene. As a result of the electron deficient nature of boron compounds, borophenes exhibit multiple phases with contrasting network structures. The present study employs novel graph theoretical techniques based on neighborhood degree-sum parameters that provide refined bond partitions to characterize the different phases of borophene nanoribbons. We have applied these techniques to the β12 and χ3 phases of borophene nanoribbons. We have also employed computer-assisted combinatorial techniques to generate the boron NMR spectra of different phases of the borophene nanoribbons.

Nanointerconnect design based on edge fluorinated/hydrogenated zigzag borophene nanoribbons: an ab initio analysis.

Using an ab initio framework and non-equilibrium Green's function technique, the effect of hydrogen and fluorine atom passivation on the electronic and transport properties of borophene nanoribbons (BNRs) are explored. For zigzag edge states, we have explored all potentially stable combinations of hydrogen and fluorine passivation. Fluorine passivation leads to thermodynamically stable structures with improved stability for the increased concentration of F atoms, according to our binding energy (Eb) calculations. Furthermore, density-of-states and dispersion relation (E-k structures) computations indicate that fluorine-passivated BNRs are primarily metallic in nature. We proposed these nanostructures for their use in metal interconnects because of their increased metallicity. We have used the typical two-probe setup to calculate the critical parameters like quantum resistance (RQ), kinetic inductance (LK), and quantum capacitance (CQ) to evaluate their performance as metal interconnects. Because they have the lowest estimated values of LK = 26.1 nH μm-1, and CQ = 399 pF cm-1, the zigzag BNRs (ZBNRs) with two edge fluorinated (F-BNR-F) nanostructures may be considered as a promising candidate for nanoscale interconnect applications.

Enhanced electron transport and self-similarity in quasiperiodic borophene nanoribbons with line defects.

Recent experiments have revealed multiple borophene phases of distinct lattice structures, suggesting that the unit cells of ν1/6 and ν1/5 boron sheets, namely α and β chains, serve as building blocks to assemble into novel borophene phases. Motivated by these experiments, we present a theoretical study of electron transport along two-terminal quasiperiodic borophene nanoribbons (BNRs), with the arrangement of the α and β chains following the generalized Fibonacci sequence. Our results indicate that the energy spectrum of these quasiperiodic BNRs is multifractal and characterized by numerous transmission peaks. In contrast to the Fibonacci model that all the electronic states should be critical, both delocalized and critical states appear in the quasiperiodic BNRs, where the averaged resistance saturates at the inverse of one conductance quantum for the delocalized states in the large length limit and contrarily exhibits a power-law dependence on the nanoribbon length for the critical states. Besides, the self-similarity is observed from the transmission spectrum, where the conductance curves overlap at different energy regions of two quasiperiodic BNRs of different Fibonacci indices and the resistance curves are analogous to each other at different energy scales of a single quasiperiodic BNR. These results complement previous studies on quasiperiodic systems where the multifractal energy spectrum and the self-similarity are observed by generating quasiperiodic potential energies, suggesting that borophene may provide an intriguing platform for understanding the structure-property relationships and exploring the physical properties of quasiperiodic systems.

Hydrogen passivated [formula omitted]-borophene nanoribbon: A propitious one-dimensional metallic anode for sodium-ion rechargeable batteries

Synthesized borophene nanoribbons are the single-atom-thick self-assembly of light weight boron atoms separated by hexagonal hole arrays. In this current study, van der Waals corrected density functional theory have been employed to inspect the interaction of Na with both edge hydrogen passivated β12-borophene nanoribbon, based upon first-principles calculations. It is found that the six member ring site is favorable location for Na insertion. Gradual decrease in adsorption energies is observed with increasing Na concentration owing to the fact that the number of vacant sites on anchoring nanoribbon decreases and metal–metal electrostatic repulsion increases. The chemical stoichiometry of full sodiated nanoribbon corresponds to B11H2Na7 with a maximum gravimetric capacity of 1551.65 mAhg−1 without the sacrifice of Na mobility (diffusion barrier of 0.38 eV). Bader charge investigation reveals that 0.83|e| is transferred from Na atom, implying high electronic conductivity of B33H6 nanoribbon during the adsorption process. The average insertion potential is obtained as 0.66 V versus Na/Na+, lying into 0.1–1 V desirable anode potential range. Our study confirm that β12-borophene nanoribbon holds a great potential to act as a propitious negative electrode material for sodium-ion rechargeable batteries based on its structural, electronic and electrochemical properties.

Resonant tunneling in disordered borophene nanoribbons with line defects

Recently, borophene has attracted extensive interest as the wonder material, showing that line defects (LDs) occur widely at the interface between nu _{1/5} and nu _{1/6} boron sheets. Here, we study theoretically the electron transport through two-terminal disordered borophene nanoribbons (BNRs) with random distribution of LDs. Our results indicate that LDs strongly affect the electron transport properties of BNRs. Both nu _{1/5} and nu _{1/6} BNRs exhibit metallic behavior without any LD, in agreement with experiments. While in the presence of LDs, the overall electron transport ability is dramatically decreased, but some resonant peaks of conductance quantum are found in the transmission spectrum of any disordered BNR with arbitrary arrangement of LDs. These disordered BNRs exhibit metal-insulator transition with tunable transmission gap in the insulating regime. Furthermore, two evolution phenomena of resonant peaks are revealed for disordered BNRs with different widths. These results may help for understanding structure-property relationships and designing LD-based nanodevices.

Unified model for plasmon-induced transparency with direct and indirect coupling in borophene-integrated metamaterials.

We propose, both numerically and theoretically, a uniform model to investigate the plasmonically induced transparency effect in plasmonic metamaterial consisting of dual-layer spatially separated borophene nanoribbons array. The dynamic transfer properties of light between two borophene resonators can be effectively described by the proposed model, with which we can distinguish and connect the direct and indirect coupling schemes in the metamaterial system. By adjusting the electron density and separation of two borophene ribbons, the proposed metamaterials enable a narrow band in the near-infrared region to reach high transmission. It provides a new, to the best of our knowledge, platform for optoelectronic integrated high-performance devices in the communication band.

Modulating spintronic properties of Nitrogen passivated borophene nanoribbons

We investigate the stability, magnetic, and transport features of pristine zigzag borophene nanoribbons (ZBNRs) and those edge-passivated by H and N atoms. The calculations were performed using non-equilibrium Green’s function and density functional theory approach. Our main focus is to study the transport properties of N-passivated ZBNRs. The results show that the stability of the nanoribbon increases by passivating the edges. The magnetic features of borophene nanoribbon are affected by the hanging bond of the edges. Hydrogenation can remove the magnetism on the edge, but the passivation by N atoms can increase the magnetic properties. It is revealed that the Nitrogenation causes the negative differential resistance (NDR) phenomenon and 65% spin filtering effect. The estimated Curie temperature for N atom passivated on both edges of ZBNR (NN-ZBNR) is higher than 6000 K, indicating that NN-ZBNR may be good room-temperature ferromagnetic material for spintronic applications in the future.

Quantum transport properties of bilayer borophene nanoribbons

Since British scientists Geim et al. (Novoselov K S, Geim A K, Morozov S V, Jiang D, Zhang Y, Dubonos S V, Grigorieva I V, Firsov A A &lt;ext-link ext-link-type="uri" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://doi.org/10.1126/science.1102896"&gt;2004&lt;i&gt; Science&lt;/i&gt; &lt;b&gt;306&lt;/b&gt; 666&lt;/ext-link&gt;) successfully peeded off single-layer graphene from multilayer graphite for the first time in 2004, two-dimensional materials have quickly caught the attention of scientists. Owing to its honeycomb structure, graphene exhibits many novel mechanical, thermal, electrical, and magnetic properties, which have attracted great attention and have broad application prospects in electronic devices and other fields. With the further development of research, more and more two-dimensional materials have been discovered successively, including silicene, germanene, and borylene. These two-dimensional materials have various excellent properties like graphene. Boron is one of the nearest-neighbor elements of carbon, it has proved to be able to form borophene, which has a lot of novel properties, including superconductivity and Dirac fermions. Several polymorphs of monolayer borophene have been synthesized on different metal surfaces, such as Au, Cu, Ag, Ir and Al. Using the nonequilibrium Green's function, we investigate the electronic transport properties of bilayer borophene which was synthesized recently. We first calculate the transmission spectra of different interlayer transition strengths when the electrode has two layers, then we calculate the currents of bilayer borophene under different voltages when the electrode has two layers, which both show bilayer borophene is metallic. With the enhancement of the interlayer transition strength, its conductivity first increases and then decays. We try to change the layer number of electrode. In scheme two, the left electrode is the lower half of the bilayer borophene while the right electrode is the upper half of the bilayer borophene. In scheme three both electrodes are the lower half of the bilayer borophene. In scheme four, both electrodes are the upper half of the bilayer borophene. In scheme five, the left electrode is the upper half of the bilayer borophene while the right electrode is the lower half of the bilayer borophene. We discover that the current decays greatly when the electrode is just one layer. For scheme three and scheme four, both left electrode and right electrode are the lower half of the bilayer borophene or the upper half of the bilayer borophene, the current will rise or decline in volatility. For scheme two or scheme five, the electrode is unsymmetrical, we find that the current will reach a maximum when interlayer transition increases. The reason for the above phenomenon is that the electrical conductivity of the upper half of the bilayer borophene is higher than that of the lower half, which causes the electrons of the lower half of the bilayer borophene to tunnel to the upper half so that the conductivity of bilayer borophene is enhanced when the interlayer transition strength is weak. However, when the interlayer transition strength is great, the frequent interlayer transition of electrons results in large scattering, thus causing its conductivity to decay. Finally, we consider the influence of the on-site disorder on the transport properties of the bilayer borophene, finding that its transport capability will be declined by increasing the disorder strength.

Hydrogenated/Fluorinated Phase Borophene Nanoribbons as Nano-Interconnects

Density functional theory (DFT) together with non-equilibrium Green's function (NEGF) is used for the theoretical investigation of structural, electronic, and transport properties of zigzag <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$v_{1/6}-30^{\circ }$</tex-math></inline-formula> phase borophene nanoribbons (BNRs). Pristine and fluorinated <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$v_{1/6}-30^{\circ }$</tex-math></inline-formula> phase BNRs are considered for the nanoscale interconnect design. The binding energy computations indicate the improvement in the structural stability of the BNRs with increase in fluorine concentration. The E-k relations reveal the hydrogen (H) and fluorine (F) passivated BNRs are metallic. The quantum transport properties are evaluated using the two-probe geometry method. The current-voltage (I-V) behavior of the considered BNR devices are linear with applied bias. Further, interconnect distributed model is explored and the dynamical parameters are evaluated. The Fermi velocity ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$v_{f}$</tex-math></inline-formula> ) is measured to be highest for the H and F passivated BNR (F-BNR-H) of about 3.784 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\times 10^{4}$</tex-math></inline-formula> m/s. The dynamic parameters for the nanoscale interconnects are improved upon fluorinating the BNRs. The calculated values of quantum resistance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$R_{Q}$</tex-math></inline-formula> ), quantum capacitance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$C_{Q}$</tex-math></inline-formula> ) and kinetic inductance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$L_{K}$</tex-math></inline-formula> ) for F-BNR-H are 1.845 K <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Omega$</tex-math></inline-formula> , 28.61 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$nF/m$</tex-math></inline-formula> , and 24.38 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$nH/\mu m$</tex-math></inline-formula> , respectively. Further, F-BNR-H device is found to have relatively lower delay from delay calculations. The stability and frequency analysis determine that the F-BNR-H has superior stability and bandwidth as compared to Cu interconnects. The interconnect performance is found to reduce with edge roughness and line parasitic effects. These theoretical findings suggest the fluorinated BNRs can be potentially used as the metal interconnect at nanoscale dimensions.

Dynamic magnetic properties of borophene nanoribbons with core-shell structure: Monte Carlo study

In this work, we applied Monte Carlo simulation to investigate the dynamic magnetic behaviors of the ferrimagnetic mixed-spin (3/2, 5/2) Ising-type borophene nanoribbons with core-shell structure. The effects of the crystal field, exchange couplings and time-dependent oscillating magnetic field on the dynamic magnetic characteristics were discussed. In addition, the hysteresis behaviors of the system were also presented and the multiple-loop hysteresis phenomena were observed.

The effect of edges hydrogenation and adsorption of Co and Mn atoms on spin transport properties of borophene Nanoribbons

The stability and magnetic features of bare (ZBNRs) and hydrogenated zigzag borophene nanoribbons (H-ZBNRs) are studied. The calculations are performed using density functional theory and non-equilibrium Green’s function. The results indicate that by hydrogenating borophene, the stability of nanoribbon increases. The magnetic properties of ZBNRs are affected by the hanging bond ofnanoribbon. ZBNR is a magnetic metal while by t hydrogenation, the magnetic effect is eliminated. The quantum transport properties for borophene nanoribbon at zero and low bias voltages are investigated. By increasing voltage the current increases and at the bias voltage of 0.5 V a current of about 35 µ A is observed. Moreover, the effect of Mn and Co adsorption on the surface of H-ZBNRs is investigated. The results indicate that the non-magnetic structure of H-ZBNRs becomes magnetic by adsorbing Co and Mn atoms. Also, the charge transfer is from Co and Mn atoms to borophene Nanoribbon. Our calculations indicate that the amount of current and the magnetic properties of ZBNRs could be modified by passivated of edge Nanoribbon and the TM atoms, which has a promising application in molecular magnet and Nano-electronic devices.