9,797 research outputs found
Gutzwiller density functional calculations of the electronic structure of FeAs-based superconductors: Evidence for a three-dimensional Fermi surface
The electronic structures of FeAs-compounds strongly depend on the
Fe-As bonding, which can not be described successfully by the local density
approximation (LDA). Treating the multi-orbital fluctuations from -
by LDA+Gutzwiller method, we are now able to predict the correct Fe-As
bond-length, and find that Fe-As bonding-strength is 30% weaker, which will
explain the observed "soft phonon". The bands are narrowed by a factor of 2,
and the orbital is pushed up to cross the Fermi level, forming
3-dimensional Fermi surfaces, which suppress the anisotropy and the ()
nesting. The inter-orbital Hund's coupling rather than plays crucial
roles to obtain these results.Comment: 4 pages, 4 figures, 1 tabl
Collective synchronization induced by epidemic dynamics on complex networks with communities
Much recent empirical evidence shows that \textit{community structure} is
ubiquitous in the real-world networks. In this Letter, we propose a growth
model to create scale-free networks with the tunable strength (noted by ) of
community structure and investigate the influence of community strength upon
the collective synchronization induced by SIRS epidemiological process. Global
and local synchronizability of the system is studied by means of an order
parameter and the relevant finite-size scaling analysis is provided. The
numerical results show that, a phase transition occurs at from
global synchronization to desynchronization and the local synchronization is
weakened in a range of intermediately large . Moreover, we study the impact
of mean degree upon synchronization on scale-free networks.Comment: 5 pages, 4 figures. to appeared in Phys. Rev. E 75 (2007
Tris(1,10-phenanthroline-κ2 N,N′)nickel(II) bis(2,4,5-tricarboxybenzoate) monohydrate
In the title compound, [Ni(C12H8N2)3](C10H5O8)2·H2O, the NiII cation is coordinated by six N atoms of the three bidentate chelating 1,10-phenanthroline ligands in a slightly distorted octahedral coordination geometry. The Ni—N bond lengths range from 2.074 (2) to 2.094 (2) Å. The dihedral angles between the three chelating NCCN groups to each other are 85.71 (3), 73.75 (2) and 85.71 (3)°, respectively. The Ni cation, the phenyl ring of the 1,10-phenanthroline ligand and the lattice water molecule are located on special positions (site symmetry 2). In the crystal, the uncoordinated 2,4,5-tricarboxybenzenoate anions join with each other through O—H⋯O hydrogen bonds, forming a two-dimensional hydrogen-bonded layer structure along the bc plane. The layers are further linked via additional O—H⋯O interactions between water and carboxyl groups, resulting in a three-dimensional supramolecular network
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