The authors report two anomalies in the specific heat of (Ba,K)Fe2As2, providing thermodynamic confirmation of the separation of superconducting Tc and the onset of time-reversal symmetry breaking (TRSB). Further, they argue that the TRSB is associated with a four-fermion condensate induced by phase fluctuations.
- Ilya Shipulin
- Nadia Stegani
- Vadim Grinenko
