168,437 research outputs found
Existence of Multistring Solutions of the Self-Gravitating Massive Boson
We consider a semilinear elliptic system which include the model system of
the strings in the cosmology as a special case. We prove existence of
multi-string solutions and obtain precise asymptotic decay estimates near
infinity for the solutions.
As a special case of this result we solve an open problem posed in
\cite{yan}Comment: 12 page
On electron (anti)localization in graphene
We discuss localization properties of the Dirac-like electronic states in
monolayers of graphite. In the framework of a general disorder model, we
identify the conditions under which such standard localization effects as
logarithmic temperature-dependent conductivity corrections appear to be
strongly suppressed, as compared to the case of a two-dimensional electron gas
with parabolic dispersion, in agreement with recent experimental observations.Comment: Latex, no figure
The structural, mechanical, electronic, optical and thermodynamic properties of t-XAs (X Si, Ge and Sn) by first-principles calculations
The structural, mechanical, electronic, optical and thermodynamic properties
of the t-XAs (X Si, Ge and Sn) with
tetragonal structure have been investigated by first principles calculations.
Our calculated results show that these compounds are mechanically and
dynamically stable. By the study of elastic anisotropy, it is found that the
anisotropic of the t-SnAs is stronger than that
of t-SiAs and
t-GeAs. The band structures and density of states
show that the t-XAs (Si, Ge and Sn) are
semiconductors with narrow band gaps. Based on the analyses of electron density
difference, in t-XAs As atoms get electrons, X
atoms lose electrons. The calculated static dielectric constants,
, are 15.5, 20.0 and 15.1 eV for
t-XAs (X Si, Ge and Sn), respectively. The
Dulong-Petit limit of t-XAs is about 10 J
molK. The thermodynamic stability successively
decreases from t-SiAs to
t-GeAs to t-SnAs.Comment: 14 pages, 10 figures, 6 table
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