Correlations among Tc, A, and Γ ο within FL region of T-p phase diagram of heavy-Fermion superconductors

Abstract

Extensively reported experimental observations indicate that on varying a control parameter, such as pressure p, within the phase diagram of most quantum critical heavy fermion HF superconductors, one identifies a cascade of distinct electronic states which may be magnetic, of Kondo-type, non-conventional superconducting, Fermi Liquid, FL, or non-FL character. Of particular interest is the part of the phase diagram wherein superconductivity emerges from a strongly renormalized FL state. This region resembles the overdoped region of the T-doping phase diagram of cuprate superconductors. Remarkably, within this highly nontrivial region, one identifies a universal correlation among Tc and (θ is a characteristic energy scale and A is the coefficient of T 2 resistivity term). Commonly, these features are considered to be driven by a Spin-Fluctuation-mediated electron-electron scattering channel. On adopting such a channel and applying standard theories of Migdal-Eliashberg (superconductivity) and Boltzmann (transport), we derive analytic expressions that satisfactorily reproduce the aforementioned empirical correlations.