113 research outputs found
Comment on "Band structure engineering of graphene by strain: First-principles calculations"
In their first-principles calculations of the electronic band structure of
graphene under uniaxial strain, Gui, Li, and Zhong [Phys. Rev. B \textbf{78},
075435 (2008)] have found opening of band gaps at the Fermi level. This finding
is in conflict with the tight-binding description of graphene which is closed
gap for small strains. In this Comment, we present first-principles
calculations which refute the claim that strain opens band gaps in graphene.Comment: published versio
Energy gap opening in submonolayer lithium on graphene: Local density functional and tight-binding calculations
The adsorption of an alkali-metal submonolayer on graphene occupying every
third hexagon of the honeycomb lattice in a commensurate
arrangement induces an energy gap in the
spectrum of graphene. To exemplify this type of band gap, we present \textit{ab
initio} density functional theory calculations of the electronic band structure
of CLi. An examination of the lattice geometry of the compound system shows
the possibility that the nearest-neighbor hopping amplitudes have alternating
values constructed in a Kekul\'e-type structure. The band structure of the
textured tight-binding model is calculated and shown to reproduce the expected
band gap as well as other characteristic degeneracy removals in the spectrum of
graphene induced by lithium adsorption. More generally we also deduce the
possibility of energy gap opening in periodic metal on graphene compounds
CM if is a multiple of 3.Comment: 7 pages, 5 figures, published versio
Numerical simulation of the stochastic dynamics of inclusions in biomembranes in presence of surface tension
The stochastic dynamics of inclusions in a randomly fluctuating biomembrane
is simulated. These inclusions can represent the embedded proteins and the
external particles arriving at a cell membrane. The energetics of the
biomembrane is modelled via the Canham-Helfrich Hamiltonian. The contributions
of both the bending elastic-curvature energy and the surface tension of the
biomembrane are taken into account. The biomembrane is treated as a
two-dimensional sheet whose height variations from a reference frame is treated
as a stochastic Wiener process. The lateral diffusion parameter associated with
this Wiener process coupled with the longitudinal diffusion parameter obtained
from the standard Einsteinian diffusion theory completely determine the
stochastic motion of the inclusions. It is shown that the presence of surface
tension significantly affects the overall dynamics of the inclusions,
particularly the rate of capture of the external inclusions, such as drug
particles, at the site of the embedded inclusions, such as the embedded
proteins.Comment: 17 pages, 4 figures, to appear in physica
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Molecular dynamics simulation of observed c(4x4) and c(4x3) C60 alignments on the Si(100) reconstructed surface.
We have implemented a large-scale classical molecular dynamics simulation at constant temperature to provide a theoretical insight into the results of a recently performed experiment on the monolayer and multi-layer formations of molecular films on the Si(100) reconstructed dimerized surface. Our simulation has successfully reproduced all of the morphologies observed on the monolayer film by this experiment. We have obtained the formation of both c(4 4) and c(4 3) structures of the molecules and have also obtained phase transitions of the former into the latter
Thermal conductivity of deformed carbon nanotubes
We investigate the thermal conductivity of four types of deformed carbon
nanotubes by using the nonequilibrium molecular dynamics method. It is reported
that various deformations have different influence on the thermal properties of
carbon nanotubes. For the bending carbon nanotubes, the thermal conductivity is
independent on the bending angle. However, the thermal conductivity increases
lightly with XY-distortion and decreases rapidly with Z-distortion. The thermal
conductivity does not change with the screw ratio before the breaking of carbon
nanotubes but decreases sharply after the critical screw ratio.Comment: 6figure
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