Searcharxiv⌕ Search

arXiv subjects

L. A. Ribeiro

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

2 recordsLinked to original sources

Unveiling a Novel Silicene-Like Material: A DFT Study on Pentahexoctite-Silicon and Its Optoelectronic Characteristics

Silicon-based two-dimensional (2D) materials, including well-known silicene, have garnered considerable attention due to their potential in advanced electronic and optoelectronic applications. Here, we introduce a novel 2D silicon variant, pentahexoctite silicon (PH-Si), inspired by the unique structural attributes of pentahexoctite carbon. By using state-of-the-art density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations, we investigated the fundamental optoelectronic traits of PH-Si. Our findings unveil that PH-Si boasts promising electronic properties characterized by anisotropic conductance and metallic behavior along specific directions. We also examine its structural and dynamic stability through phonon calculations and AIMD simulations. PH-Si structural stability was also confirmed by its low formation energy of -3.62 eV. The material exhibits substantial optical absorption in visible (Vis) and ultraviolet (UV) spectral regions, positioning it as a potential Vis-UV detector and absorber. Additionally, we assess its crucial mechanical attributes, encompassing elastic stiffness constants, Young's modulus (ranging from 5 to 40 GPa), and a Poisson ratio of 0.8, collectively offering valuable insights into its mechanical performance.

cond-mat.mtrl-sci↗

On the Mechanical Properties of Popgraphene-based Nanotubes: a Reactive Molecular Dynamics Study

Carbon-based tubular materials have sparked a great interest for future electronics and optoelectronics device applications. In this work, we computationally studied the mechanical properties of nanotubes generated from popgraphene (PopNTs). Popgraphene is a 2D carbon allotrope composed of $5-8-5$ rings. We carried out fully atomistic reactive (ReaxFF) molecular dynamics for PopNTs of different chiralities ($(n,0)$ and $(0,n)$) and/or diameters and at different temperatures (from 300 up to 1200K). Results showed that the tubes are thermally stable (at least up to 1200K). All tubes presented stress/strain curves with a quasi-linear behavior followed by an abrupt drop of stress values. Interestingly, armchair-like PopNTs ($(0,n)$) can stand a higher strain load before fracturing when contrasted to the zigzag-like ones ($(n,0)$). Moreover, it was obtained that the Young's modulus ($Y_{Mod}$) (750-900 GPa) and ultimate strength ($σ_{US}$) (120-150 GPa) values are similar to the ones reported for conventional armchair and zigzag carbon nanotubes. $Y_{Mod}$ values obtained for PopNTs are not significantly temperature dependent. While the $σ_{US}$ values for the $(0,n)$ showed a quasi-linear dependence with the temperature, the $(n,0)$ exhibited no clear trends.

cond-mat.mtrl-sci↗