Endline of Pseudogap in overdoped cuprates
Recent light scattering measurements performed in our group have reveal that the onset of the pseudogap is connected to a change in the Fermi surface topology
S. Benhabib et al. arXiv:1403.7620 (2014)
Doping evolution of a antinodal gap intensity showing a Lifschitz transition in overdoped Bi2212 cuprate. The pseudogap in the normal state opens at the same doping content.
Higgs mode in charge density wave superconductors
Oscillations in the amplitude of the superconducting order parameter, or Higgs mode, can be detected optically when there is a coexisting charge density wave order. We show this by comparing NbS2 and NbSe2 compounds which differ only on the presence (absence) of a coexisting charge density wave order.
M.A. Méasson et al. Phys. Rev. B 89, 060503(R) (2014)
Collective amplitude and phase modes of the superconducting (SC) order parameter.
Raman spectra of NbSe2 and NbS2 showing a much weaker SC Higgs mode when no charge density wave (CDW) is present.
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Nematicity in iron based superconductors
Measurement in the normal state of iron based superconductors show the presence of charge nematic fluctuations throughout the phase diagram of 122 compounds. They establish Raman scattering as a key probe to detect these fluctuations in correlated electron systems.
Y. Gallais et al. Phys. Rev. Lett. 111, 267001 (2013)
Phase diagram of Nematic fluctuation in Co doped BaFe2As2 as detected by polarized electronic Raman scattering.