Continuum of Irreversible and Potentially Reversible Traumatic Brain Injury Sequelae: Axonal Injury and Hydrocephalus.
Authors: Vargas-Ardila PA, Rondón M, Bonilla-Lersundy MC, Vargas-Ardila AF, Chacón-Zambrano LA
Journal: Korean journal of neurotrauma
PTSD treatment
mental health
open access
Abstract
Carbon’s structural
versatility spans hybridization states
from three-dimensional sp diamond to two-dimensional sp graphene and one-dimensional sp carbyne, making it uniquely
suited as a single-element platform for atomically precise nanoelectronics. Among two-dimensional allotropes, graphene nanoribbons (GNRs) with
armchair and zigzag edge topologies display strikingly different electronic
characters, including width-dependent semiconducting gaps vs localized
magnetic edge states, and bottom-up on-surface synthesis has made
atomically precise ribbons experimentally accessible with confirmed
transistor action and topological in-gap states. Beyond the purely hexagonal network of graphene, phagraphene, a
2D sp allotrope built from alternating pentagonal, hexagonal,
and heptagonal rings, hosts distorted Dirac cones and supports width-dependent
topological insulator-to-metal transitions in nanoribbon form. Related nonhexagonal sp networks, including biphenylene
(4–6–8 rings), have already been realized experimentally
by on-surface synthesis, establishing
that 2D carbon networks incorporating nonhexagonal rings are accessible
materials with distinct transport properties. Carbyne, the sp-hybridized
one-dimensional allotrope, exhibits extraordinary mechanical stiffness
and strongly geometry-dependent conductance; its synthesis and stabilization
inside carbon nanotubes and by on-surface demetallization routes have
advanced markedly. The integration of carbyne chains as atomically defined electrodes
contacting 2D nanoribbon scattering regions creates a hybrid sp–sp junction family whose transport properties depend simultaneously
on ring topology, edge orientation, and electrode contact geometry.
Prior density functional theory combined with the nonequilibrium Green’s
function formalism (DFT/NEGF) studies have addressed these contributions
individually: phagraphene nanoribbon width and doping, graphene-phagraphene heterojunctions, and sp-carbon chain contacts to SWCNT and metal electrodes. However, a systematic study simultaneously varying ring topology
(graphene vs phagraphene), edge orientation (zigzag vs armchair),
and contact site within a controlled device family has not been reported,
leaving the interplay of these degrees of freedom and the emergent
design rules unquantified. Here, we report a first-principles
DFT/NEGF study of eight device
configurations. By varying the nanoribbon ring composition and electrode
attachment while keeping the architecture fixed, we isolate the effects
of topology, edge orientation, and contact geometry on transport.
A comparison between graphene and phagraphene families provides design
rules for molecular-wire, rectifier, and sensing applications in atomically
precise sp–sp carbon nanoelectronics.
versatility spans hybridization states
from three-dimensional sp diamond to two-dimensional sp graphene and one-dimensional sp carbyne, making it uniquely
suited as a single-element platform for atomically precise nanoelectronics. Among two-dimensional allotropes, graphene nanoribbons (GNRs) with
armchair and zigzag edge topologies display strikingly different electronic
characters, including width-dependent semiconducting gaps vs localized
magnetic edge states, and bottom-up on-surface synthesis has made
atomically precise ribbons experimentally accessible with confirmed
transistor action and topological in-gap states. Beyond the purely hexagonal network of graphene, phagraphene, a
2D sp allotrope built from alternating pentagonal, hexagonal,
and heptagonal rings, hosts distorted Dirac cones and supports width-dependent
topological insulator-to-metal transitions in nanoribbon form. Related nonhexagonal sp networks, including biphenylene
(4–6–8 rings), have already been realized experimentally
by on-surface synthesis, establishing
that 2D carbon networks incorporating nonhexagonal rings are accessible
materials with distinct transport properties. Carbyne, the sp-hybridized
one-dimensional allotrope, exhibits extraordinary mechanical stiffness
and strongly geometry-dependent conductance; its synthesis and stabilization
inside carbon nanotubes and by on-surface demetallization routes have
advanced markedly. The integration of carbyne chains as atomically defined electrodes
contacting 2D nanoribbon scattering regions creates a hybrid sp–sp junction family whose transport properties depend simultaneously
on ring topology, edge orientation, and electrode contact geometry.
Prior density functional theory combined with the nonequilibrium Green’s
function formalism (DFT/NEGF) studies have addressed these contributions
individually: phagraphene nanoribbon width and doping, graphene-phagraphene heterojunctions, and sp-carbon chain contacts to SWCNT and metal electrodes. However, a systematic study simultaneously varying ring topology
(graphene vs phagraphene), edge orientation (zigzag vs armchair),
and contact site within a controlled device family has not been reported,
leaving the interplay of these degrees of freedom and the emergent
design rules unquantified. Here, we report a first-principles
DFT/NEGF study of eight device
configurations. By varying the nanoribbon ring composition and electrode
attachment while keeping the architecture fixed, we isolate the effects
of topology, edge orientation, and contact geometry on transport.
A comparison between graphene and phagraphene families provides design
rules for molecular-wire, rectifier, and sensing applications in atomically
precise sp–sp carbon nanoelectronics.