à 
amphitheatre (salle 1035)
5155, chemin de la rampe
Montréal (QC) Canada  H3T 2B2

The quantum critical point of cuprate superconductors
Louis Taillefer
Institut Quantique, Département de physique, Université de Sherbrooke
Canadian Institute for Advanced Research, Toronto, Canada

Abstract: By suppressing superconductivity with a large magnetic field, we have investigated the metallic ground state of several cuprate superconductors in the T = 0 limit (YBCO, Bi2212, LSCO, Nd-LSCO, Eu-LSCO, Bi2201), via measurements of resistivity, Hall and Seebeck coefficients, thermal conductivity and specific heat. We observe a sharp transition at a critical doping p*, into the enigmatic pseudogap phase. The key signature is a drop in carrier density n from n = 1 + p above p* to n = p below p* [1,2], signaling a major transformation of the Fermi surface. At p*, we observe the classic signatures of quantum criticality: the electrical resistivity is linear in T at low T [2,3,4] and the electronic specific heat Cel shows a sharp peak at p*, where it varies in temperature as Cel ~ – T logT [5]. Understanding the mechanisms responsible for these various signatures will help elucidate the nature of the enigmatic pseudogap phase of cuprates.
[1] Badoux et al., Nature 531, 210 (2016).
[2] Collignon et al., Phys. Rev. B 95, 224517 (2017).
[3] Daou et al., Nat. Phys. 5, 31 (2009).
[4] Legros et al., arXiv:1805.02512.
[5] Michon et al., arXiv:1804.08502.

Lien vers le site web du professeur Taillefer.

Cette conférence est présentée par le RQMP Versant Nord du Département de physique de l'Université de Montréal et de Génie physique de la Polytechnique.

The quantum critical point of cuprate superconductors - Louis Taillefer (Sherbrooke)