arXiv subjects

L. A. Ribeiro Junior

Publications and source records attributed to L. A. Ribeiro Junior.

18 recordsLinked to original sources

arXiv2025

Novel 3D Pentagraphene Allotropes: Stability, Electronic, Mechanical, and Optical Properties

Carbon-based materials have attracted great attention due to their exceptional structural diversity and wide-ranging applications. Recently, a new two-dimensional carbon allotrope, named pentagraphene (PG), was proposed. In this study, we proposed three novel three-dimensional (3D) PG allotropes, named 3D-PG-$α$, -$β$, and -$γ$, engineered through biaxial strain and controlled compression of 2D PG layers. Comprehensive stability analyses, including phonon dispersion and ab initio molecular dynamics simulations (AIMD), confirm their thermodynamic stability under room and high-temperature conditions. 3D-PG-$α$ is the most stable, exhibiting a cohesive energy 0.5 eV/atom lower than the least stable structure, 3D-PG-$γ$. Electronic property characterization reveals semiconducting behavior for all structures, with indirect electronic band gaps ranging from 0.91 to 2.67 eV. The analyses of the mechanical properties showed significant anisotropy, with higher stiffness along the in-plane ($xy$-plane) direction. Optical properties highlight strong absorption along a wide range and a pronounced anisotropic response. Additionally, the absorption spectra exhibit activity in the visible region, and the refractive index and reflectivity indicate potential use in ultraviolet-blocking devices.

cond-mat.mtrl-sci↗

arXiv2025

Propylenidene: A Novel Metallic Carbon Monolayer with Unconventional Ring Topology

Two-dimensional (2D) carbon allotropes have drawn significant interest owing to their impressive physical and chemical characteristics. Following graphene's isolation, a wide range of 2D carbon materials has been suggested, each with distinct electronic, mechanical, and optical traits. Rational design and synthesis of new 2D carbon structures hinge on experimentally reported precursors. Here, we present a 2D carbon allotrope, propylenidene (PPD), originating from bicyclopropylidene. PPD forms a rectangular lattice with 3, 8, and 10-membered carbon rings. Density functional theory (DFT) simulations investigate its structural, electronic, mechanical, and optical properties. Our study shows PPD to be metallic. PPD exhibits absorption in the infrared and visible range, showing directional dependence in its response. Mechanically, PPD exhibits marked anisotropy; Young's modulus ($Y$) varies between 205.83 N/m and 164.46 N/m. These findings underscore the potential of this novel monolayer in applications such as energy storage, gas sensing, and optoelectronics.

cond-mat.mtrl-sci↗

arXiv2025

Entangled Interlocked Diamond-like (Diamondiynes) Lattices

Diamondynes, a new class of diamond-like carbon allotropes composed of carbon with sp$^2$/sp$^3$-hybridized carbon networks, exhibit unique structural motifs that have not been previously reported in carbon materials. These architectures feature sublattices that are both interlocked and capable of relative movement. Using ab initio simulations, we have conducted an extensive investigation into the structural and electronic properties of five diamondyne structures. Our results show that diamondiynes are thermodynamically stable and exhibit wide electronic band gaps, from 2.2 eV to 4.0 eV. They are flexible yet highly resistant compared to other diamond-like structures. They have relatively small cohesive energy values, consistent with the fact that one diamondyne structure (2f-unsym) has already been experimentally realized. Our results provide new physical insights into diamond-like carbon networks and suggest promising directions for the development of porous, tunable frameworks with potential applications in energy storage and conversion.

cond-mat.mtrl-sci↗

arXiv2025

HOP-graphene: A high-capacity anode for Li/Na-ion batteries unveiled by first-principles calculations

The growing demand for efficient energy storage has driven the search for advanced anode materials for lithium- and sodium-ion batteries (LIBs and SIBs). In this context, we report the application of HOP-graphene (a 5-6-8-membered 2D carbon framework) as a high-performance anode material for LIBs and SIBs using density functional theory simulations. Diffusion studies reveal low energy barriers of 0.70 eV for Li and 0.39 eV for Na, indicating superior mobility at room temperature compared to other carbon allotropes, like graphite. Full lithiation and sodiation accommodate 24 Li and 22 Na atoms, respectively, delivering outstanding theoretical capacities of 1338 mAh/g (Li) and 1227 mAh/g (Na). Bader charge analysis and charge density difference maps confirm substantial electron transfer from the alkali metals to the substrate. Average open-circuit voltages of 0.42 V (Li) and 0.33 V (Na) suggest favorable electrochemical performance. HOP-graphene also demonstrates excellent mechanical strength. These findings position HOP-graphene as a promising candidate for next-generation LIB and SIB anodes.

cond-mat.mtrl-sci↗

arXiv2025

Anthraphenylenes: Porous 2D Carbon Monolayers with Biphenyl-Anthracene Frameworks and Type-II Dirac line nodes

Carbon's versatility allows it to form diverse structures with unique properties, driven by its moderate electronegativity, small ionic radius, and ability to adopt \textit{sp}, \textit{sp\textsuperscript{2}}, and \textit{sp\textsuperscript{3}} hybridizations, individually or in combination. In this work, we introduce three novel 2D carbon allotropes -- $α$, $β$, and $γ$-anthraphenylenes -- derived from biphenylene and Dewar-anthracene motifs, investigated through density functional theory calculations. Their thermodynamic and dynamic stability are confirmed by cohesive energy ($-7.02$ to $-7.26$ eV/atom), phonon dispersion, and \textit{ab initio} molecular dynamics simulations. The electronic structure analysis shows that all three anthraphenylenes display metallic behavior. All anthraphenylenes feature type-II Dirac Line Nodes (DLNs). Mechanical analysis highlights significant anisotropy, mainly in $γ$-anthraphenylene, which exhibits the highest rigidity. These monolayers feature a porous architecture with tunable mechanical properties, making them promising candidates for nanoelectronics and energy storage applications. By expanding the family of 2D carbon materials, anthraphenylenes provide new avenues for functional nanomaterial design.

cond-mat.mtrl-sci↗

arXiv2025

From 2D to 1D in beta-Naphthyne: A Porous Carbon Allotrope Merging Graphyne and Naphthylene

Two-dimensional (2D) carbon-based materials have attracted considerable interest due to their diverse structural and electronic properties, making them ideal for next-generation flat electronics. Among these materials, metallic-like porous structures offer advantages such as tunable charge transport and high surface area, which are essential for energy storage applications. In this study, we introduce beta-naphthyne, a novel 2D carbon allotrope composed of naphthyl units interconnected by octagonal rings. First-principles calculations confirm its dynamic and thermal stability, demonstrating its theoretical feasibility. Our results confirm its energetic, dynamic, and mechanical stability and its metallic nature. Furthermore, we demonstrate that Young's modulus ranges from 46.60 N/m to 164.47 N/m, indicating an anisotropic mechanical response. Optical analysis reveals absorption activity in the infrared (IR) and ultraviolet (UV) regions. The 1D structures were also analyzed, revealing a Dirac cone and a transition from metallic to semiconducting behavior. These findings establish beta-naphthyne as a promising material for energy storage and optoelectronic technologies.

cond-mat.mtrl-sci↗

arXiv2024

Exploring the Electronic and Mechanical Properties of the Recently Synthesized Nitrogen-Doped Monolayer Amorphous Carbon

The recent synthesis of nitrogen-doped monolayer amorphous carbon (MAC @N) opens new possibilities for multifunctional materials. In this study, we have investigated the nitrogen doping limits and their effects on MAC@N's structural and electronic properties using density functional-based tight-binding simulations. Our results show that MAC@N remains stable up to 35\% nitrogen doping, beyond which the lattice becomes unstable. The formation energies of MAC@N are higher than those of nitrogen-doped graphene for all the cases we have investigated. Both undoped MAC and MAC@N exhibit metallic behavior, although only MAC features a Dirac-like cone. MAC has an estimated Young's modulus value of about 410 GPa, while MAC@N's modulus can vary around 416 GPa depending on nitrogen content. MAC displays optical activity in the ultraviolet range, whereas MAC@N features light absorption within the infrared and visible ranges, suggesting potential for distinct optoelectronic applications. Their structural thermal stabilities were addressed through molecular dynamics simulations. MAC melts at approximately 4900K, while MAC@N loses its structural integrity for temperatures ranging from 300K to 3300K, lower than graphene. These results point to potential MAC@N applications in flexible electronics and optoelectronics.

cond-mat.mtrl-sci↗

arXiv2023

TODD-Graphene: A Novel Porous 2D Carbon Allotrope for High-Performance Lithium-Ion Batteries

The class of 2D carbon allotropes has garnered significant attention due to its exceptional optoelectronic and mechanical properties, crucial for diverse device applications, such as energy storage. This study employs density functional theory calculations, ab initio molecular dynamics (AIMD), and classical reactive (ReaxFF) molecular dynamics (MD) simulations to introduce TODD-Graphene, a novel 2D planar carbon allotrope with a porous structure composed of 3-8-10-12 carbon rings. TODD-G exhibits intrinsic metallic properties with low formation energy and demonstrates exceptional dynamic, thermal, and mechanical stability. Calculations reveal a high theoretical capacity for adsorbing Li atoms by showing a low average diffusion barrier of 0.83 eV and a metallic framework boasting excellent conductivity, emerging as a promising anode material for lithium-ion batteries. We also calculated the charge carrier mobility for electrons and holes in TOOD-G, and the values surpassed the graphene ones. Classical reactive MD simulation results suggested its structural integrity with no bond reconstructions at 1800 K.

cond-mat.mtrl-sci↗

arXiv2023

Predicting Psi-BN: computational insights into its mechanical, electronic, and optical characteristics

Computational materials are pivotal in advancing our understanding of distinct material classes and their properties, offering valuable insights in predicting novel structures and complementing experimental approaches. In this context, Psi-graphene is a stable two-dimensional carbon allotrope composed of 5-6-7 carbon rings theoretically predicted recently. Using density functional theory (DFT) calculations, we explored its boron nitride counterpart's mechanical, electronic, and optical characteristics (Psi-BN). Our results indicate that Psi-BN possesses a band gap of 4.59 eV at the HSE06 level. Phonon calculations and ab initio molecular dynamics simulations demonstrated that this material has excellent structural and dynamic stability. Moreover, its formation energy is -7.48 eV. Psi-BN exhibited strong ultraviolet activity, suggesting its potential as an efficient UV collector. Furthermore, we determined critical mechanical properties of Psi-BN, such as the elastic stiffness constants, Young's modulus (250-300 GPa), and Poisson ratio (0.7), providing valuable insights into its mechanical behavior.

cond-mat.mtrl-sci↗

arXiv2023

Lattice Thermal Conductivity of 2D Nanomaterials: A Simple Semi-Empirical Approach

Extracting reliable information on certain physical properties of materials, like thermal behavior, such as thermal transport, which can be very computationally demanding. Aiming to overcome such difficulties in the particular case of lattice thermal conductivity (LTC) of 2D nanomaterials, we propose a simple, fast, and accurate semi-empirical approach for its calculation.The approach is based on parameterized thermochemical equations and Arrhenius-like fitting procedures, thus avoiding molecular dynamics or \textit{ab initio} protocols, which frequently demand computationally expensive simulations. As proof of concept, we obtain the LTC of some prototypical physical systems, such as graphene (and other 2D carbon allotropes), hexagonal boron nitride (hBN), silicene, germanene, binary, and ternary BNC latices and two examples of the fullerene network family. Our values are in good agreement with other theoretical and experimental estimations, nonetheless being derived in a rather straightforward way, at a fraction of the computational cost.

cond-mat.mtrl-sci↗

arXiv2023

Nanomechanical behavior of pentagraphyne-based single-layer and nanotubes through reactive classical molecular dynamics

In a recent theoretical study, a new 2D carbon allotrope called pentagraphyne (PG-yne) was proposed. This allotrope is derived from pentagraphene by introducing acetylenic linkages between sp3 and sp2 hybridized carbon atoms. Due to its interesting electronic and structural properties, it is of interest to investigate the mechanical behavior of PG-yne in both monolayer and nanotube topologies. To achieve this, we performed fully atomistic reactive (ReaxFF) molecular dynamics simulations, and our results show that Young's modulus average of PG-yne monolayers is approximately 913 GPa, at room temperature. In comparison, it ranges from 497-789 GPa for the nanotubes studied. Furthermore, we observed that PG-yne monolayers exhibit a direct transition from elastic to complete fracture under critical strain without a plastic regime. In contrast, some PG-yne nanotubes exhibit an extended flat plastic regime before total fracture.

physics.comp-ph↗

arXiv2023

Unveiling the CO2 Adsorption Capabilities of Biphenylene Network Monolayers through DFT Calculations

Nanomaterial synthesis and characterization advancements have led to the discovery of new carbon allotropes, such as the biphenylene network (BPN). BPN consists of four-, six-, and eight-membered rings of sp2-hybridized carbon atoms. Here, we employ density functional theory (DFT) calculations to investigate the CO2 adsorption capabilities in pristine and vacancy-endowed BPN monolayers. Our findings indicate that BPN lattices with a single-atom vacancy exhibit higher CO2 adsorption energies than pristine BPN. Unlike other 2D carbon allotropes, BPN does not exhibit precise CO2 sensing and selectivity by altering its band structure configuration. In pristine lattices, CO2 molecules are physisorbed in the eight-membered rings, while defective regions of vacancy-endowed lattices enable chemisorption of CO2. Regarding CO2 physisorption, the recovery time values are minimal, suggesting a rapid interaction between BPN and this molecule, with negligible relaxation time required to alter the electronic properties of BPN lattices.

cond-mat.mtrl-sci↗

arXiv2023

First-Principles and Reactive Molecular Dynamics Study of the Elastic Properties of Pentahexoctite-based Nanotubes

Pentahexoctite (PH) is a pure sp$^2$ hybridized planar carbon allotrope whose structure consists of a symmetric combination of pentagons, hexagons, and octagons. The proposed PH structure was shown to be an intrinsically metallic material exhibiting good mechanical and thermal stability. PH nanotubes (PHNTs) have also been proposed, and their properties were obtained from first principles calculations. Here, we carried out fully-atomistic simulations, combining reactive (ReaxFF) molecular dynamics (MD) and density functional theory (DFT) methods, to study the PHNTs elastic properties and fracture patterns. We have investigated the mechanical properties behavior as a function of the tube diameter and temperature regimes. Our results showed that the PHNTs, when subjected to large tensile strains, undergo abrupt structural transitions exhibiting brittle fracture patterns without a plastic regime.

cond-mat.mtrl-sci↗

arXiv2022

Quantum Biochemical Analysis of the TtgR Regulator and Effectors

The recent expansion of multidrug-resistant (MDR) pathogens poses significant challenges in treating healthcare-associated infections. Although antibacterial resistance occurs by numerous mechanisms, active efflux of the drugs is a critical concern. A single species of efflux pump can produce a simultaneous resistance to several drugs. One of the best-studied efflux pumps is the TtgABC: a tripartite resistance-nodulation-division (RND) efflux pump implicated in the intrinsic antibiotic resistance in Pseudomonas putida DOT-T1E. The expression of the TtgABC gene is down-regulated by the HTH-type transcriptional repressor TtgR. In this context, by employing quantum chemistry methods based on the Density Functional Theory (DFT) within the Molecular Fragmentation with Conjugate Caps (MFCC) approach, we investigate the coupling profiles of the transcriptional regulator TtgR in complex with quercetin (QUE), a natural polyphenolic flavonoid, tetracycline (TAC), and chloramphenicol (CLM), two broad-spectrum antimicrobial agents. Our quantum biochemical computational results show the: [i] convergence radius, [ii] total binding energy, [iii] relevance (energetically) of the ligands regions, and [iv] most relevant amino acids residues of the TtgR-QUE/TAC/CLM complexes, pointing out distinctions and similarities among them. These findings improve the understanding of the binding mechanism of effectors and facilitate the development of new chemicals targeting TtgR, helping in the battle against the rise of resistance to antimicrobial drugs.

physics.bio-ph↗

arXiv2022

2D Porphyrazine: A New Nanoporous Material

Crystalline microporous materials are solids formed by interconnected pores of less than 2 nm in size. Typically, they possess large surface areas desirable for versatile applications such as catalysis, gas adsorption, and energy storage. In the present work, we propose a new porphyrin-based 2D nanoporous crystal, named 2D Porphyrazine (2DP), which is formed by topological assembling H$_{5}$C$_{13}$N$_{4}$ porphyrins. We have considered its monolayer, bi-layer, and molecular crystal (bulk) arrangements. We carried out DFT calculations to investigate 2DP structural and electronic properties. Results show that 2DP is a very stable structure with a direct bandgap of 0.65 eV and significant optical absorption in the visible range. 2DP exhibited satisfactory affinity to lithium atoms. Simulations also showed the existence of proton transfer between nitrogen atoms. It is the first report on the site-specific hydrogen exchange process in 2D crystals.

cond-mat.mtrl-sci↗

arXiv2022

Irida-Graphene: A New 2D Carbon Allotrope

Several 2D carbon-based materials have been computationally designed in the last years due to the success achieved by graphene. Here, we propose a new 2D all-sp$^2$ carbon allotrope, named Irida-Graphene (IG), using a bottom-up approach. IG is composed of fused rings containing 3-6-8 carbon atoms. We employed density functional theory calculations and reactive (ReaxFF) molecular dynamics simulations to examine its mechanical, structural, electronic, and optical properties. Results showed that IG exhibits good dynamical and thermal stabilities. Its estimated elastic modulus varies between 80-113 GPa. IG is a metallic material and presents a Dirac cone above the Fermi level in the center of the band. The intense optical activity of IG is restricted to the infrared and violet regions. IG can act as a violet collector for photon energies of about 3.0 eV since it presents very low reflectivity and refractive index greater than one.

cond-mat.mtrl-sci↗

arXiv2022

Thermal Stability and Fracture Patterns of a Recently Synthesized Monolayer Fullerene Network: A Reactive Molecular Dynamics Study

New monolayer 2D carbon structures, namely qHPC60 and qTPC60, were recently synthesized by covalently bonding C60 polymers. Here, we carried out Reactive (ReaxFF) molecular dynamics simulations to study the thermodynamic stability and fracture patterns of qHPC60 and qTPC60. Our results showed that these structures present similar thermal stability, with sublimation points of 3898K and 3965K, respectively. qHPC60 and qTPC60 undergo an abrupt structural transition becoming totally fractured after a critical strain threshold. The crack propagation is linear (non-linear) for qHPC60 (qTPC60). The estimated elastic modulus for qHPC60 and qTPC60 are 175.9 GPa and 100.7 GPa, respectively.

cond-mat.mtrl-sci↗

arXiv2020

On the Elastic Properties of Single-Walled Phagraphene Nanotubes

Phagraphene (PhaG) is a quasi-planar 2D structure composed of $5-6-7$ ring sequence. We have investigated the structural and mechanical properties of phagraphene nanotubes (PhaNTs) through fully atomistic reactive molecular dynamics (MD) simulations. For comparison purposes, the results were also contrasted to similar carbon nanotubes (CNTs). Results showed that PhaNTs and CNTs present similar brittle fracture mechanisms. The Young's modulus values obtained for PhaNTs were smaller than the corresponding ones for CNTs. Both, PhaNTs and CNTs, present equivalent fracture strains ranging between 15\%-20\%. For the ultimate strength values, CNTs present values about 30\% higher than the corresponding ones for PhaNTs.

cond-mat.mtrl-sci↗