(QC) Canada

New experimental signatures of the pseudogap phase in cuprates
Louis Taillefer
Département de physique
Université de Sherbrooke

Présentation en anglais

Vidéoconférence, Zoom #: 81007662178 (Zoom link)
Lorsque demandé, indiquer 'Un Sept Quatre Neuf' en chiffre.

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, by 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], signalling a major transformation of the Fermi surface. From specific heat measurements, we observe the classic thermodynamic signatures of quantum criticality: the electronic specific heat shows a sharp peak at p*, where it varies in temperature as – T logT [3]. 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 [4]. Finally, the pseudogap phase is found to have a large negative thermal Hall conductivity, as a result of phonons acquiring chirality in a magnetic field [5].

[1] Proust & Taillefer, Annu. Rev. Condens. Matter Phys. 10, 409 (2019).
[2] Badoux et al., Nature 531, 210 (2016); Collignon et al., Phys. Rev. B 95, 224517 (2017).
[3] Michon et al., Nature 567, 218 (2019).
[4] Legros et al., Nat. Phys. 15, 142 (2019); Grissonnanche et al., Nature 595, 667 (2021).
[5] Grissonnanche et al., Nature 571, 376 (2019); Nat. Phys. 16, 1108 (2020).

Cette conférence est présentée par le RQMP.

New experimental signatures of the pseudogap phase in cuprates - Louis Taillefer (UdeS)