Anomalous isotope Effect in d-wave superconductors on the square lattice

Gan Sun, Qing-Geng Yang, Da Wang +1

Isotope effect with a large coefficient $\hat{I}\pm =-\partial \ln T_c/\partial \ln M$ is usually taken as an evidence of phonon mediated superconductors in the Bardeen-Cooper-Schrieffer (B…