Day / Time
Date(s) - 03/03/2015
13 h 00 min - 14 h 00 min
Ecole de Physique, Auditoire Stueckelberg, 24 quai Ernest-Anserme
« Fermi surface reconstruction by charge order in the pseudogap phase of underdoped copper oxides »
Laboratoire National des Champs Magnétiques Intenses, Toulouse, France.
Over the last years, quantum oscillation measurements  have shown that the Fermi surface of underdoped cuprates suffer a drastic modification compare to the large hole-like cylinder observed in the overdoped side . Many studies such as NMR measurements , x-ray scattering  point to a reconstruction of the Fermi surface due to charge density wave (CDW). Fermi-surface reconstruction and charge modulations are two universal signatures of underdoped cuprates, which begs the following questions: what is the impact of charge order on the electronic properties of underdoped cuprates ? Is the Fermi surface seen by quantum oscillations compatible with a reconstruction by CDW modulations?
After an introduction starting from the observation of quantum oscillations to the discovery of charge order in cuprates, I will present thermodynamic and transport measurements in underdoped cuprates performed in high magnetic fields demonstrating that a phase transition takes place at low temperature. Compelling evidence that the Fermi surface of YBa2Cu3Oy is reconstructed by the CDW order detected by x-ray diffraction comes from the recent discovery of an additional small hole-like pocket in quantum oscillations measurements . The consistency between our quantum oscillation measurements and models of Fermi-surface reconstruction by the CDW order will be discussed. N. Doiron-Leyraud et al, Nature 447, 565 (2007), N. Barisic et al, Nature Physics 9, 761 (2013)  B. Vignolle et al, Nature 455, 952 (2008)  T. Wu et al, Nature 477, 191 (2011)  G. Ghiringhelli et al , Science 337, 821 (2012) / J. Chang et al, Nature Physics 8, 871 (2012)  N. Doiron-Leyraud et al, Nature Communications 6, 6034 (2015)