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Mardi 26 Juin, 14h
Amphi Howleck, Esc C, 1ème etage
Controling Parameters of Tc in Unconventional Superconductors
Y.J. Uemura
Columbia University
Accumulation of experimental data on unconventional superconductors
has shown various correlations between Tc and possible controling
parameters, including superfluid density, resonance mode energy,
gap energy, spin fluctuation energy J, and possibly others.
I have been advocating two view points
(1) Charge energy scale (T_F) derived from superfluid density and
spin energy scale (J) are often comparable, and together
determine evolution of Tc versus doping / pressurizing.
(2) The resonance mode energy, like rotons in superfluid He,
represents closeness of the superconducting state to the competing
(magnetic) state, and works as an additional separate parameter
in addition to T_F and J.
In this talk, I will discuss these pictures with recent results in
CeCo(In,Sn)5 and FeAs supercondutors.