2001/11/30 by Giorgio Sangiovanni, G. Sangiovanni, Massimo Capone +5
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.67.174507
published as Phys. Rev. B 67, 174507 (2003) · 8 pages, 3 figures. Expanded text, 1 extra figure
openalex publication_date 2003/05/08 · arxiv created 2004/01/21 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Motivated by recent tunneling and Andreev-reflection experiments, we study the conditions for a quantum transition within the superconducting phase of the cuprates, in which a bulk imaginary (time-reversal breaking) idxy component appears in addition to the d_x2\ensuremath-y2 order parameter. We examine in detail the role of some important physical features of the cuprates. In particular we show that a closed Fermi surface, a bilayer splitting, an orthorhombic distortion, and the proximity to a quantum critical point around optimal doping favor the appearance of the imaginary component. These findings could explain why the mixed d_x2\ensuremath-y2+idxy order parameter is observed in Y_1\ensuremath-yCayBa2Cu3O_7\ensuremath-x and La_2\ensuremath-xSrxCuO4, and suggest that it could appear also in Bi2Sr2CaCu2O8. We also predict that, in all cuprates, the mixed state should be stable only in a limited doping region all contained beneath the d_x2\ensuremath-y2 dome. The behavior of the specific heat at the secondary transition is discussed.