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Eduardo C. Girão

Publications and source records attributed to Eduardo C. Girão.

2 recordsLinked to original sources

Electronic, structural and magnetic properties of goldene nanoribbons

Recently, two-dimensional goldene, a single-atomic-layer gold sheet, has been experimentally realized and is expected to be a promising material for next-generation devices, offering new possibilities beyond three-dimensional bulk gold. Because quasi-one-dimensional derivatives can exhibit properties markedly different from their two-dimensional counterparts, we investigate the stability, electronic, and magnetic properties of goldene-based nanoribbons (GOLDNRs) using first-principles computational methods. Our findings demonstrate that the electronic structure of these nanoribbons depends strongly on both edge chirality and ribbon width. Depending on the boundary configuration, the systems can exhibit semiconducting behavior with electronic band gaps of approximately 0.77 eV and 0.04 eV, or retain metallic characteristics. Additionally, the edge regions act as electronically active sites that may significantly enhance chemical reactivity relative to the central regions. As the ribbon width increases, the metallic characteristics of the infinite goldene sheet are progressively recovered, while the influence of quantum confinement and edge effects on the central region diminishes. These results provide important insights into tailoring the physical properties of goldene through lateral confinement, highlighting its potential for applications in nanoscale field-effect transistors, spintronic devices, and catalysis.

cond-mat.mtrl-sci↗

Mechanical Properties of Pentagraphene-based Nanotubes: A Molecular Dynamics Study

The study of the mechanical properties of nanostructured systems has gained importance in theoretical and experimental research in recent years. Carbon nanotubes (CNTs) are one of the strongest nanomaterials found in nature, with Young's Modulus (YM) in the order 1.25 TPa. One interesting question is about the possibility of generating new nanostructures with 1D symmetry and with similar and/or superior CNT properties. In this work, we present a study on the dynamical, structural, mechanical properties, fracture patterns and YM values for one class of these structures, the so-called pentagraphene nanotubes (PGNTs). These tubes are formed rolling up pentagraphene membranes (which are quasi-bidimensional structures formed by densely compacted pentagons of carbon atoms in sp3 and sp2 hybridized states) in the same form that CNTs are formed from rolling up graphene membranes. We carried out fully atomistic molecular dynamics simulations using the ReaxFF force field. We have considered zigzag-like and armchair-like PGNTs of different diameters. Our results show that PGNTs present YM ~ 800 GPa with distinct elastic behavior in relation to CNTs, mainly associated with mechanical failure, chirality dependent fracture patterns and extensive structural reconstructions.

cond-mat.mes-hall↗