New signatures of the pseudogap phase of cuprate superconductors
Institut Quantique, University of Sherbrooke, Sherbrooke
Canada Canadian Institute for Advanced Research, Canada
Présentation en anglais
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Abstract: The pseudogap phase of cuprate superconductors is arguably the most enigmatic phase of quantum matter. We aim to shed new light on this phase by investigating the non-superconducting ground state of several cuprate materials at low temperatures across a wide doping range, suppressing superconductivity with a magnetic field .
Hall effect and thermal conductivity measurements across the pseudogap critical doping p* reveal a sharp drop in carrier density n from n = 1 + p above p* to n = p below p* [2,3], signaling a major transformation of the Fermi surface. From specific heat measurements, we observe the classic thermodynamic signatures of quantum criticality: the electronic specific heat C el shows a sharp peak at p*, where it varies in temperature as C el ~ – T logT . At p* and just above, the electrical resistivity is linear in T at low T, with an inelastic scattering rate that obeys the Planckian limit . Finally, the pseudogap phase is found to have a large negative thermal Hall conductivity, which extends to zero doping . We show that the pseudogap phase makes phonons become chiral .
Understanding the mechanisms responsible for these various new signatures will help elucidate the nature of the pseudogap phase.
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