1303.2010 (Sergey L. Bud'ko et al.)

Heat capacity jump at Tc and pressure derivatives of superconducting
transition temperature in the Ba1-xKxFe2As2 (0.2 < x < 1.0) series    [PDF]

Sergey L. Bud'ko, Mihai Sturza, Duck Young Chung, Mercouri G. Kanatzidis, Paul C. Canfield

We present the evolution of the initial (up to ~ 10 kbar) hydrostatic, pressure dependencies of Tc and of the ambient pressure jump in the heat capacity associated with the superconducting transition as a function of K - doping in the Ba1-xKxFe2As2 family of iron-based superconductors. The pressure derivatives show weak but distinct anomaly near x ~ 0.7. In the same concentration region Delta Cp at Tc deviates from the Delta Cp ~ T^3 scaling found for most BaFe2As2 - based superconductors. These results are consistent with a Lifshitz transition, and possible significant modification of the superconducting state, occurring near x ~ 0.7.

View original: http://arxiv.org/abs/1303.2010