arXiv subjects

Luiz A. Ribeiro Jr

Publications and source records attributed to Luiz A. Ribeiro Jr.

10 recordsLinked to original sources

arXiv2026

Phase-Dependent Excitonic Light Harvesting and Photovoltaic Limits in Monolayer Y2TeO2 MOenes

We investigate phase-dependent electronic and excitonic phenomena in monolayer Y2TeO2 MOenes in the 1T and 2H polymorphs using first-principles theory and an effective many-body framework. Phonon spectra and elastic stability criteria establish both phases as dynamically and mechanically stable. Quasiparticle band structures reveal direct gaps in the near-infrared to visible range, with gap values increasing systematically from semilocal to hybrid exchange treatments. Optical spectra computed using a tight-binding Bethe-Salpeter approach demonstrate pronounced excitonic resonances arising from reduced dimensionality and weak dielectric screening. The exciton binding energies reach 152 meV in the 1T phase and 126 meV in the 2H phase, reflecting enhanced quantum confinement in the structurally denser phase. Our results identify Y2TeO2monolayers as a rare class of stable, direct-gap MOenes with strong excitonic effects, providing a platform for exploring many-body physics in low-dimensional oxychalcogenide systems especially for photovoltaic applications.

physics.comp-ph↗

arXiv2026

Exploring the Potential of Two-dimensional Borospherene for Toxic Gas Sensing and Capture: A DFT Study

Two-dimensional (2D) boron-based materials have gained increasing interest due to their exceptional physicochemical properties and potential technological applications. In this way, borospherenes, a 2D Boron-based fullerene-like lattice (2D-B40), are explored due to their potential for capturing and detecting toxic gases, such as CO, NO, NH3, and SO2. Therefore, density functional theory simulations were carried out to explore the adsorption energy and the distinct interaction regimes, where CO exhibits weak physisorption (-0.16 eV), while NO (-2.24 eV), NH3 (-1.47 eV), and SO2 (-1.51 eV) undergo strong chemisorption. Bader charge analysis reveals significant electron donation from 2D-B40 to NO and electron acceptance from SO2. These interactions cause measurable shifts in work function, with SO2 producing the most significant modulation (14.6%). Remarkably, ab initio molecular dynamics simulations (AIMD) reveal spontaneous SO2 decomposition at room temperature, indicating dual functionality for both sensing and environmental remediation. Compared to other boron-based materials, such as chi3-borophene, beta12-borophene, and B40 fullerene, 2D-B40 exhibits superior gas affinity, positioning it as a versatile platform for the detection and capture of toxic gases.

cond-mat.mtrl-sci↗

arXiv2026

Goldene monolayer as a highly effective catalyst for polysulfide anchoring and conversion: A theoretical study

We use first-principles density functional theory to investigate how lithium sulfide and polysulfide clusters (Li2S, Li2S2, Li2S4, Li2S6, Li2S8, and S8) bind to Goldene, a new two-dimensional gold allotrope. All Li-S species exhibit robust binding to Goldene. The adsorption energies range from -4.29 to -1.90 eV. S8 that is alone interacts much less strongly. Charge density difference and Bader analyses indicate that substantial charge is transferred to the substrate, with a maximum 0.92 e for Li-rich clusters. This transfer induces polarization at the interface and shifts the work function to 5.30-5.52 eV. Projected density-of-states calculations indicate that Au-d and S-p states strongly mix near the Fermi level. This hybridization indicates that the electronic coupling is strong. Based on these results, the reaction free-energy profile for the stepwise conversion of S8 to Li2S on Goldene is thermodynamically favorable. The overall stabilization is -3.64 eV, and the rate-determining barrier for the Li2S2 -> Li2S step is 0.47 eV. This shows that Goldene is an effective surface for anchoring and mediating lithium polysulfide reactions.

cond-mat.mtrl-sci↗

arXiv2025

A Three-Dimensional Dodecaphenylyne-Derived Carbon Allotrope with Anisotropic and Auxetic-Like Mechanical Behavior

We introduce 3D-DPhyne, a novel three-dimensional (3D) carbon allotrope derived from the dodecaphenylyne framework, and investigate its structural, electronic, optical, and mechanical properties using first-principles calculations. The proposed structure forms a tetragonal, topologically complex network of four-, six-, and twelve-membered carbon rings with mixed sp/sp^2 hybridization and a formation energy of -7.87 eV/atom, comparable to other stable carbon allotropes. Phonon dispersion calculations show no imaginary modes, and ab initio molecular dynamics simulations at 1000~K confirm robust thermal stability without bond breaking. Electronic structure analysis reveals metallic character, with multiple bands crossing the Fermi level and dominant contributions from carbon p orbitals, consistent with a fully delocalized 3D $π$-conjugated network. The optical response is anisotropic, exhibiting strong absorption in the visible and ultraviolet regions and low reflectivity across a broad range of photon energies. Mechanical analysis reveals pronounced elastic anisotropy, with Young's modulus varying from approximately 40 to 490 GPa depending on direction. Poisson's ratio displays unconventional directional behavior, including auxetic-like responses.

cond-mat.mtrl-sci↗

arXiv2025

Kagome Topology in Two-Dimensional Noble-Metal Monolayers

Two-dimensional (2D) metallic lattices with kagome topology provide a unique platform for exploring the interplay between geometric frustration, reduced coordination, and lattice stability in elemental systems. Motivated by the recent experimental realization of atomically thin gold layers and kagome goldene, we present a first-principles investigation of free-standing kagome monolayers of Cu, Ag, and Au. Using density functional theory combined with lattice dynamics and ab initio molecular dynamics, we systematically assess their structural, mechanical, dynamical, and thermal stability. All kagome monolayers satisfy the 2D Born criteria and exhibit relatively low in-plane stiffness compared to graphene and hexagonal goldene, reflecting the porous nature of the kagome lattice and its metallic bonding. Among the three systems, the Au-based lattice displays the highest in-plane Young's modulus. Phonon calculations reveal that the unstrained kagome phase is dynamically unstable for all metals. However, a moderate biaxial tensile strain of 5% stabilizes the Ag and Au monolayers, while Cu retains residual unstable modes. Finite-temperature simulations further show that Cu rapidly reconstructs toward a trigonal lattice, Ag remains metastable at low temperature but collapses at room temperature, and Au exhibits competing kagome and trigonal motifs at 300 K, indicating near-degeneracy between these phases. These results establish that strain engineering and atomic size are key determinants of the stability of metallic kagome monolayers and provide guidance for future substrate-supported realizations.

cond-mat.mtrl-sci↗

arXiv2025

Quadrene: A Novel Quasi-2D Carbon Allotrope with High Carrier Mobility

We present a comprehensive first-principles investigation of a novel carbon allotrope characterized by quasi-tetragonal atomic motifs and quasi-two-dimensional structural behavior. Structural analysis reveals an open framework composed of alternating diamond-like and square units, while thermodynamic assessments indicate a negative formation energy, suggesting high intrinsic stability. Phonon spectra confirm dynamical robustness, and \textit{ab initio} molecular dynamics simulations at 1000~K validate its thermal resilience. Furthermore, the system exhibits an indirect bandgap of 1.58 eV at the HSE06 level, anisotropic mechanical behavior, and a broadband optical response, reinforcing its potential for nanoelectronic and optoelectronic applications. The highly anisotropic mechanical behavior is characterized by an in-plane Young's modulus ranging from 80 to 550 GPa, depending on crystallographic direction. Additionally, the electronic transport properties exhibit pronounced anisotropy, with hole mobilities reaching up to 5.83 x 10^6 cm^2/V . s and electron mobilities up to 6.40 x 10^6 cm^2/V . s along different crystallographic directions, highlighting the material's potential for directionally selective nanoelectronic device applications.

cond-mat.mtrl-sci↗

arXiv2025

Structural Stability of Sulfur Depleted MoS2

Transition metal dichalcogenides (TMDs), particularly monolayer MoS2, have received increased attention in materials science and have been exploited in diverse applications from photonics to catalysis. Defects in TMDs play a crucial role in modulating their properties, and understanding defect-induced dynamics is of great importance. This study investigates the dynamics of sulfur depletion in defective monolayer MoS2, which yields stable MoS monolayers. Various defect sizes, temperature regimes, and substrate effects were investigated. Through comprehensive classical molecular (ReaxFF) molecular dynamics (MD) and ab initio MD (AIMD) simulations, we elucidate the dynamics of sulfur vacancy formation in MoS2 lattices. After removing all sulfur atoms from the top layer, several sulfur atoms from the bottom layer spontaneously migrate to the top layer as a response to increase structural stability, thus creating a MoSx alloy. These findings deepen our understanding of defect dynamics in TMDs, offering valuable insights into the controlled engineering of their properties for nanotechnology applications.

cond-mat.mtrl-sci↗

arXiv2025

Physicochemical Characterization of a New 2D Semiconductor Carbon Allotrope, C16: An Investigation via Density Functional Theory and Machine Learning-based Molecular Dynamics

This study comprehensively characterizes, with suggested applications, a novel two-dimensional carbon allotrope, C$_{16}$, using Density Functional Theory and machine learning-based molecular dynamics. This nanomaterial is derived from naphthalene and bicyclopropylidene molecules, forming a planar configuration with sp$^2$ hybridization and featuring 3-, 4-, 6-, 8-, and 10-membered rings. Cohesive energy of \SI{-7.1}{\electronvolt/atom}, absence of imaginary frequencies in the phonon spectrum, and the retention of the system's topology after ab initio molecular dynamics simulations confirm the structural stability of C$_{16}$. The nanomaterial exhibits a semiconducting behavior with a direct band gap of \SI{0.59}{\electronvolt} and anisotropic optical absorption in the $y$ direction. Assuming a complete absorption of incident light, it registers a power conversion efficiency of \SI{13}{\percent}, demonstrating relatively good potential for applications in solar energy conversion. The thermoelectric figure of merit ($zT$) reaches 0.8 at elevated temperatures, indicating a reasonable ability to convert a temperature gradient into electrical power. Additionally, C$_{16}$ demonstrates high mechanical strength, with Young's modulus values of \SI{500}{\giga\pascal} and \SI{630}{\giga\pascal} in the $x$ and $y$ directions, respectively. Insights into the electronic, optical, thermoelectric, and mechanical properties of C$_{16}$ reveal its promising capability for energy conversion applications.

cond-mat.mtrl-sci↗

arXiv2025

First-Principles and Machine Learning Insights into the Design of DOTT-Carbon and its Lithium-Ion Storage Capacity

Two-dimensional (2D) carbon-based materials are promising candidates for developing more efficient green energy conversion and storage technologies. This study presents a new 2D carbon allotrope, DOTT-Carbon, characterized by its distinctive and multi-ring structure featuring 12-, 8-, 4-, and 3-membered rings of carbon atoms. We explore its structural, mechanical, and lithium-ion storage properties by employing density functional theory and machine learning simulations. Phonon calculations confirm its structural stability and ab initio molecular dynamics simulations demonstrate its thermal resilience at elevated temperatures. The material exhibits anisotropic mechanical properties, with Young's modulus values varying between 280-330 GPa. DOTT-Carbon displays a lithium-ion storage capacity of 446.28 mAh/g, complemented by a low diffusion barrier (0.2-0.9 eV) and a high diffusion coefficient ($ > 1.0 \times 10^{-6}$ cm$^{2}$/s), possibly facilitating efficient lithium-ion transport. The stable open circuit voltage of 0.28 V also indicates its suitability as an anode material.

cond-mat.mtrl-sci↗

arXiv2024

Irida-Graphene Phonon Thermal Transport via Non-equilibrium Molecular Dynamics Simulations

Recently, a new 2D carbon allotrope called Irida-Graphene (Irida-G) was proposed. Irida-G consists of a flat sheet topologically arranged into 3-6-8 carbon rings exhibiting metallic and non-magnetic properties. In this study, we investigated the thermal transport properties of Irida-G using classical reactive molecular dynamics simulations. The findings indicate that Irida-G has an intrinsic thermal conductivity of approximately 215 W/mK at room temperature, significantly lower than that of pristine graphene. This decrease is due to characteristic phonon scattering within Irida-G's porous structure. Additionally, the phonon group velocities and vibrational density of states for Irida-G were analyzed, revealing reduced average phonon group velocities compared to graphene. The thermal conductivity of Irida-G is isotropic and shows significant size effects, transitioning from ballistic to diffusive heat transport regimes as the system length increases. These results suggest that while Irida-G has lower thermal conductivity than graphene, it still holds potential for specific thermal management applications, sharing characteristics with other two-dimensional materials.

cond-mat.mtrl-sci↗