Abstract
The recent discovery of a charge order in underdoped YBa2Cu3Oy raised the question of the interplay between superconductivity and this competing phase. Understanding the normal state of high-temperature superconductors is now an essential step towards the description of the pairing mechanism in those materials and determining the upper critical field is therefore of fundamental importance. We present here a calorimetric determination of the field–temperature phase diagram in underdoped YBa2Cu3Oy single crystals. We show that the specific heat saturates in high magnetic fields. This saturation is consistent with a normal state without any significant superconducting contribution and a total Sommerfeld coefficient γN∼6.5±1.5 mJ mol−1 K−2 putting strong constraints on the theoretical models for the Fermi surface reconstruction.
Highlights
The recent discovery of a charge order in underdoped YBa2Cu3Oy raised the question of the interplay between superconductivity and this competing phase
To overcome the problem to estimate this lattice contribution, we have subtracted from all curves the data obtained at 14 T, a high enough field to strongly suppress most of the anomaly, being a good approximation of the normal state specific heat in this temperature range
The overall shape of the anomaly is intermediate between the highly asymmetric jump measured in optimally doped YBCO, and the symmetric cusps with no underlying mean-field contribution observed in very
Summary
The recent discovery of a charge order in underdoped YBa2Cu3Oy raised the question of the interplay between superconductivity and this competing phase. We show that the specific heat saturates in high magnetic fields This saturation is consistent with a normal state without any significant superconducting contribution and a total Sommerfeld coefficient gNB6.5±1.5 mJ mol À 1 K À 2 putting strong constraints on the theoretical models for the Fermi surface reconstruction. The specific heat saturates in high magnetic fields with a total Sommerfeld coefficient gNB6.5±1.5 mJ mol À 1 K À 2 putting strong constraints on the theoretical models for the Fermi surface reconstruction. This saturation is consistent with a normal state without any significant superconducting contribution, in contradiction to previous experimental results[15]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
