Lifshitz transitions and correlation effects in unconventional superconductors (Vol. 47 No. 2)

Unconventional superconductivity is observed in heavy fermion systems, cuprates, molecular crystals, and iron-based superconductors close to a point in the phase diagram where as a function of a control parameter (pressure or doping), the antiferromagnetic order is suppressed. A widespread view is that at this point, which is called a quantum critical point (QCP), strong antiferromagnetic fluctuations are a candidate for the glue mediating superconductivity and also account for the normal state non-Fermi-liquid behaviour. Recent ARPES results on ferropnictides have shown that in these compounds the non-Fermi-liquid like scattering rate does not diverge at the QCP, as expected in the quantum critical scenario. Rather, near the QCP it is constant over a large range of the control parameter. In this study, a new scenario is proposed using minimum model calculations: a co-action of hole vanishing Lifshitz transitions and correlation effects is able to explain the ARPES results as well as the strange normal state transport and thermal properties.

J. Fink, Influence of Lifshitz transitions and correlation effects on the scattering rates of the charge carriers in iron-based superconductors, EPL 113, 27002 (2016)
[Abstract]