Séminaire RQMP: Louis Taillefer

Date : 9 July 2020 10:30

Type : Institut Quantique

Location :

New signatures of the pseudogap phase of cuprate superconductors
Louis Taillefer
Institut Quantique, University of Sherbrooke, Sherbrooke
Canada Canadian Institute for Advanced Research, Canada

Présentation en anglais

Vidéoconférence, Zomm #: 892019835 (Zoom link)
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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 [1].

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 [4]. 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 [5]. Finally, the pseudogap phase is found to have a large negative thermal Hall conductivity, which extends to zero doping [6]. We show that the pseudogap phase makes phonons become chiral [7].

Understanding the mechanisms responsible for these various new signatures will help elucidate the nature of the pseudogap phase.

[1] Proust & Taillefer, Annual Review of Condensed Matter Physics 10, 409 (2019); arXiv:1807.07054.
[2] Badoux et al., Nature 531, 210 (2016).
[3] Collignon et al., Physical Review B 95, 224517 (2017).
[4] Michon et al., Nature 567, 218 (2019).
[5] Legros et al., Nature Physics 15, 142 (2019).
[6] Grissonnanche et al., Nature 571, 376 (2019).
[7] Grissonnanche et al., Nature Physics (in press); arXiv:2003.00111.

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