415 research outputs found
Long-Range Coulomb Effect on the Antiferromagnetism in Electron-doped Cuprates
Using mean-field theory, we illustrate the long-range Coulomb effect on the
antiferromagnetism in the electron-doped cuprates. Because of the Coulomb
exchange effect, the magnitude of the effective next nearest neighbor hopping
parameter increases appreciably with increasing the electron doping
concentration, raising the frustration to the antiferromagnetic ordering. The
Fermi surface evolution in the electron-doped cuprate NdCeCuO
and the doping dependence of the onset temperature of the antiferromagnetic
pseudogap can be reasonably explained by the present consideration.Comment: 4 pages, 4 figure
Antiferromagnetism and Superconductivity in layered organic conductors: Variational cluster approach
The -(ET)X layered conductors (where ET stands for BEDT-TTF) are
studied within the dimer model as a function of the diagonal hopping
and Hubbard repulsion . Antiferromagnetism and d-wave superconductivity are
investigated at zero temperature using variational cluster perturbation theory
(V-CPT). For large , N\'eel antiferromagnetism exists for ,
with . For fixed , as is decreased (or pressure
increased), a superconducting phase appears. When is
decreased further, the a order takes over. There is a critical value
of of beyond which the AF and dSC phases are separated
by Mott disordered phase.Comment: 4 pages, 4 figures. Investigation of the d_xy phase added +
discussion of gap symmetr
Tunneling between edge states in a quantum spin Hall system
We analyze a quantum spin Hall (QSH) device with a point contact connecting
two of its edges. The contact supports a net spin tunneling current that can be
probed experimentally via a two-terminal resistance measurement. We find that
the low-bias tunneling current and the differential conductance exhibit scaling
with voltage and temperature that depend nonlinearly on the strength of the
electron-electron interaction.Comment: 4 pages, 3 figures; published versio
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