Change of carrier density at the pseudogap critical point of a cuprate superconductor

Sven Badoux (1) , Wojciech Tabis (2, 3) , Francis Laliberté (2) , Gaël Grissonnanche (1) , Baptiste Vignolle (2) , David Vignolles (2) , Jérome Béard (2) , D.A. Bonn (4, 5) , W. Hardy (4, 5) , R. Liang (5, 4) , Nicolas Doiron-Leyraud (1) , Louis Taillefer (1, 5) , Cyril Proust (2, 5)

1 RQMP - Regroupement Québécois sur les Matériaux de Pointe
2 LNCMI-T - Laboratoire national des champs magnétiques intenses - Toulouse
3 AGH UST - AGH University of Science and Technology [Krakow, PL]
4 Department of Physics and Astronomy [Vancouver]
5 CIFAR - Canadian Institute for Advanced Research

The pseudogap is a partial gap in the electronic density of states that opens in the normal (non-superconducting) state of cuprate superconductors and whose origin is a long-standing puzzle. Its connection to the Mott insulator phase at low doping (hole concentration, p) remains ambiguous1 and its relation to the charge order2,3,4 that reconstructs the Fermi surface5,6 at intermediate doping is still unclear7,8,9,10. Here we use measurements of the Hall coefficient in magnetic fields up to 88 tesla to show that Fermi-surface reconstruction by charge order in the cuprate YBa2Cu3Oy ends sharply at a critical doping p = 0.16 that is distinctly lower than the pseudogap critical point p* = 0.19 (ref. 11). This shows that the pseudogap and charge order are separate phenomena. We find that the change in carrier density n from n = 1 + p in the conventional metal at high doping (ref. 12) to n = p at low doping (ref. 13) starts at the pseudogap critical point. This shows that the pseudogap and the antiferromagnetic Mott insulator are linked.

Domaines: Supraconductivité [cond-mat.supr-con]

Sven Badoux, Wojciech Tabis, Francis Laliberté, Gaël Grissonnanche, Baptiste Vignolle, et al.. Change of carrier density at the pseudogap critical point of a cuprate superconductor. Nature, 2016, 531 (7593), pp.210-214. ⟨10.1038/nature16983⟩. ⟨hal-01719714⟩