30,426 research outputs found
Cylindrical Superlens by a Coordinate Transformation
Cylinder-shaped perfect lens deduced from the coordinate transformation
method is proposed. The previously reported perfect slab lens is noticed to be
a limiting form of the cylindrical lens when the inner radius approaches
infinity with respect to the lens thickness. Connaturality between a
cylindrical lens and a slab lens is affirmed by comparing their eigenfield
transfer functions. We numerically confirm the subwavelength focusing
capability of such a cylindrical lens with consideration of material
imperfection. Compared to a slab lens, a cylindrical lens has several
advantages, including finiteness in cross-section, and ability in lensing with
magnification or demagnification. Immediate applications of such a cylindrical
lens can be in high-resolution imaging and lithography technologies. In
addition, its invisibility property suggests that it may be valuable for
non-invasive electromagnetic probing.Comment: Minor changes to conform with the published versio
Mott physics in electron dioxygenyl magnet : OF (=Sb, Pt)
We have investigated electronic structures and magnetic properties of
OF (=Sb, Pt), which are composed of two building blocks of
strongly correlated electrons: O dioxygenyls and F
octahedra, by employing the first-principles electronic structure band method.
For OSbF, as a reference system of OPtF, we have shown
that the Coulomb correlation of O(2) electrons drives the Mott insulating
state. For OPtF, we have demonstrated that the Mott insulating
state is induced by the combined effects of the Coulomb correlation of O(2)
and Pt(5) electrons and the spin-orbit (SO) interaction of Pt(5) states.
The role of the SO interaction in forming the Mott insulating state of
OPtF is similar to the case of SrIrO that is a
prototype of a SO induced Mott system with J.Comment: 5 pages, 6 figure
The Finite- Impurity Anderson Model in the presence of an external magnetic field
We have investigated effects of an external magnetic field in the impurity
Anderson model with a finite on-site Coulomb repulsion . Large
expansion is employed in the slave boson representation, by taking into account
, , and subspaces. To evaluate the vertex function for the
``empty state boson" self-energy, we have devised two approximations which
reduce much computational efforts without losing general features of the model.
It is found that the Kondo temperature is reduced by the presence of a magnetic
field, and that at low field and at low temperature, the field dependence of
both the Kondo temperature and the impurity magnetization exhibits a scaling
behavior with high accuracy. Further, some interesting features are found in
the field dependence of the impurity magnetization at finite temperature, the
physical implications of which are discussed in terms of the renormalized Kondo
temperature.Comment: 18 pages Revtex, 7 Postscript figures, To appear in Phys.Rev.
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