21,490 research outputs found
A new metric for rotating charged Gauss-Bonnet black holes in AdS spaces
This paper presents a new metric for slowly rotating charged Gauss-Bonnet
black holes in higher dimensional anti-de Sitter spaces. Taking the angular
momentum parameter up to second order, the slowly rotating charged black
hole solutions are obtained by working directly in the action.Comment: 11 pages and accepted by Chin. Phys.
Impurity scattering and Friedel oscillations in mono-layer black phosphorus
We study the effect of impurity scattering effect in black phosphorurene (BP)
in this work. For single impurity, we calculate impurity induced local density
of states (LDOS) in momentum space numerically based on tight-binding
Hamiltonian. In real space, we calculate LDOS and Friedel oscillation
analytically. LDOS shows strong anisotropy in BP. Many impurities in BP are
investigated using -matrix approximation when the density is low. Midgap
states appear in band gap with peaks in DOS. The peaks of midgap states are
dependent on impurity potential. For finite positive potential, the impurity
tends to bind negative charge carriers and vise versa. The infinite impurity
potential problem is related to chiral symmetry in BP
Evidence for spin-flip scattering and local moments in dilute fluorinated graphene
The issue of whether local magnetic moments can be formed by introducing
adatoms into graphene is of intense research interest because it opens the
window to fundamental studies of magnetism in graphene, as well as of its
potential spintronics applications. To investigate this question we measure, by
exploiting the well-established weak localization physics, the phase coherence
length L_phi in dilute fluorinated graphene. L_phi reveals an unusual
saturation below ~ 10 K, which cannot be explained by non-magnetic origins. The
corresponding phase breaking rate increases with decreasing carrier density and
increases with increasing fluorine density. These results provide strong
evidence for spin-flip scattering and points to the existence of adatom-induced
local magnetic moment in fluorinated graphene. Our results will stimulate
further investigations of magnetism and spintronics applications in
adatom-engineered graphene.Comment: 9 pages, 4 figures, and supplementary materials; Phys. Rev. Lett. in
pres
Effective mass of electrons and holes in bilayer graphene: Electron-hole asymmetry and electron-electron interaction
Precision measurements of the effective mass m* in high-quality bilayer graphene using the temperature dependence of the Shubnikov–de Haas oscillations are reported. In the density range 0.7 × 1012 \u3c n \u3c 4.1 × 1012 cm−2, both the hole mass m*h and the electron mass m*e increase with increasing density, demonstrating the hyperbolic nature of the bands. The hole mass m*h is approximately 20–30% larger than the electron mass m*e . Tight-binding calculations provide a good description of the electron-hole asymmetry and yield an accurate measure of the interlayer hopping parameter v4 = 0.063. Both m*h and m*e are suppressed compared with single particle values, suggesting renormalization of the band structure of bilayer graphene induced by electron-electron interaction
The quantum scattering time and its implications on scattering sources in graphene (Supplementary)
Supplementary Information Content:
1. Sample preparation;
2. Background subtraction of Shubnikov-de Haas (SdH) oscillations;
3. The effect of density inhomogeneity on the quantum scattering time tau_q;
4. Determine the concentration of charged impurity n_imp at a distance z;
5. Scattering from charges in the bulk of the SiO_2 substrate.Comment: Supplementary materials to arXiv:0909.1595. 5 pages, 5 figure
Effective mass of electrons and holes in bilayer graphene: Electron-hole asymmetry and electron-electron interaction
Precision measurements of the effective mass m* in high-quality bilayer graphene using the temperature dependence of the Shubnikov–de Haas oscillations are reported. In the density range 0.7 × 1012 \u3c n \u3c 4.1 × 1012 cm−2, both the hole mass m*h and the electron mass m*e increase with increasing density, demonstrating the hyperbolic nature of the bands. The hole mass m*h is approximately 20–30% larger than the electron mass m*e . Tight-binding calculations provide a good description of the electron-hole asymmetry and yield an accurate measure of the interlayer hopping parameter v4 = 0.063. Both m*h and m*e are suppressed compared with single particle values, suggesting renormalization of the band structure of bilayer graphene induced by electron-electron interaction
Multi-quark components in baryons
A brief review on some recent progresses in our understanding of multi-quark
components in baryons is presented. The multi-quark components in baryons seem
to be mainly in colored quark cluster configurations rather than in ``meson
cloud'' configurations or in the form of a sea of quark-antiquark pairs. The
colored quark cluster multi-quark picture gives a natural explanation of
empirical indications for a positive strangeness magnetic moment of the
proton and the longstanding mass-reverse problem of S11(1535) and \mu_s$ of the proton is given.Comment: Contribution to the International Conference on QCD and Hadronic
Physics, June 16-20, 2005, Beijin
Spin correlated interferometry for polarized and unpolarized photons on a beam splitter
Spin interferometry of the 4th order for independent polarized as well as
unpolarized photons arriving simultaneously at a beam splitter and exhibiting
spin correlation while leaving it, is formulated and discussed in the quantum
approach. Beam splitter is recognized as a source of genuine singlet photon
states. Also, typical nonclassical beating between photons taking part in the
interference of the 4th order is given a polarization dependent explanation.Comment: RevTeX, 19 pages, 1 ps figure, author web page at
http://m3k.grad.hr/pavici
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