Coexistence of Even- and Odd-Frequency Superconductivities Under Broken   Time-Reversal Symmetry
  A novel superconducting state under the broken time-reversal symmetry is studied in conventional phonon-mediated superconductors. By solving the Eliashberg equation self-consistently with the mass renormalization effect, it is found that the even- and odd-frequency components of the order parameter coexist in the bulk system as a consequence of the broken time-reversal symmetry. This finding would direct more attention to the odd-frequency pairing that affects physical quantities, especially in strong coupling superconductors. 
Masashige Matsumoto, Mikito Koga, and Hiroaki Kusunose
cond-mat.supr-con cond-mat.str-el