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Current
research highlights
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New Fe-based superconductors
The new Fe-based pnictide and chalcogenide superconductors have Tc's of up to 55K and are much more 3D than the cuprates. What makes the electrons form pairs?
Left: a density functional theory plot of the Fermi level density of
states in the BaFe2As2 system made in conjunction
with the group of H.-P. Cheng (Phys. Rev. B 80, 104511 (2009)). In left panel an Fe (gray) is substituted
by a Co (blue).
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| Defects in correlated systems Impurities induce magnetic droplets in strongly correlated systems (see Rev. Mod. Phys. 81, 45 (2009),
cover photo shown at right). The overlap of these droplets
leads to long-range antiferromagnetic order, an "order by disorder"
phenomenon enhanced by d-wave superconductivity. In
underdoped cuprates, analogies may be drawn to magnetism in the cores of vortices.
Similarities and differences were
explored in
arXiv:0912.2941. |
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Grain boundary transport
For many years an exponential decrease of the critical current at
grain boundaries of cuprate high-Tc superconductors as a function of
misonrientation angle has been observed. It is believed that this
effect limits the performance of high-Tc power transmission
applications. In arXiv:0912.4191,
we present a solution for the origin of this effect via modelling of
the charge inhomogeneity at the boundary. Left: calculated
pattern of supercurrents at a 410 boundary.
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