19,547 research outputs found
Strain induced band gap deformation of H/F passivated graphene and h-BN sheet
Strain induced band gap deformations of hydrogenated/fluorinated graphene and
hexagonal BN sheet have been investigated using first principles density
functional calculations. Within harmonic approximation, the deformation is
found to be higher for hydrogenated systems than for the fluorinated systems.
Interestingly, our calculated band gap deformation for hydrogenated/fluorinated
graphene and BN sheets are positive, while those for pristine graphene and BN
sheet are found to be negative. This is due to the strong overlap between
nearest neighbor {\pi} orbitals in the pristine sheets, that is absent in the
passivated systems. We also estimate the intrinsic strength of these materials
under harmonic uniaxial strain, and find that the in-plane stiffness of
fluorinated and hydrogenated graphene are close, but larger in magnitude as
compared to those of fluorinated and hydrogenated BN sheet.Comment: Submitted to PR
Spectral weight redistribution in (LaNiO3)n/(LaMnO3)2 superlattices from optical spectroscopy
We have studied the optical properties of four
(LaNiO)/(LaMnO) superlattices (SL) (=2, 3, 4, 5) on
SrTiO substrates. We have measured the reflectivity at temperatures from 20
K to 400 K, and extracted the optical conductivity through a fitting procedure
based on a Kramers-Kronig consistent Lorentz-Drude model. With increasing
LaNiO thickness, the SLs undergo an insulator-to-metal transition (IMT)
that is accompanied by the transfer of spectral weight from high to low
frequency. The presence of a broad mid-infrared band, however, shows that the
optical conductivity of the (LaNiO)/(LaMnO) SLs is not a linear
combination of the LaMnO and LaNiO conductivities. Our observations
suggest that interfacial charge transfer leads to an IMT due to a change in
valence at the Mn and Ni sites.Comment: Accepted for publication in Phys. Rev. Lett. 5 pages, 5 figure
On Some properties of Di-hadronic states
The binding energies of di- hadronic states have been calculated assuming a
'molecular' interaction provided by the asymptotic expression of the residual
confined gluon exchange potential between the component hadrons in the system.
Meson- meson and meson- baryon states have been studied in detail and a mass
formula has been used to calculate total mass of the 'molecules'.Comment: 11 page
Universal Scaling Property of System Approaching Equilibrium
In this Letter we show that the diffusion kinetics of kinetic energy among
the atoms in non- equilibrium crystalline systems follows universal scaling
relation and obey Levy-walk properties. This scaling relation is found to be
valid for systems no matter how far they are driven out of equilibrium.Comment: 6 pages, 4 figure
Entanglement of a Laguerre-Gaussian cavity mode with a rotating mirror
It has previously been shown theoretically that the exchange of linear
momentum between the light field in an optical cavity and a vibrating end
mirror can entangle the electromagnetic field with the vibrational motion of
that mirror. In this paper we consider the rotational analog of this situation
and show that radiation torque can similarly entangle a Laguerre-Gaussian
cavity mode with a rotating end mirror. We examine the mirror-field
entanglement as a function of ambient temperature, radiation detuning and
orbital angular momentum carried by the cavity mode.Comment: 5 figures, 1 table, submitted to Phys.Rev.
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