Interplay between superconductivity and the strange-metal state in FeSe

Universal correlation of the superconducting transition temperature with the linear-in-T coefficient, electron packing parameter, and the numbers of valence and conduction electrons

“…For simplicity, we would use the positive sign + to replace ± in eqn (9) when we do calculations for demonstration purposes. This theoretical prediction provides a strong support to recent empirical scaling phenomena observed among many different superconductors as detailed in the literature; 6,7 in particular, Fig. 3 of ref.…”

“…This theoretical prediction provides a strong support to recent empirical scaling phenomena observed among many different superconductors as detailed in the literature; 6,7 in particular, Fig. 3 of ref.…”

“…Our equations with properly chosen Taylor expansion terms can fit the experimental data in both low and high temperature regions, better than the empirical linear relationship uncovered in the literature. 6,7…”

“…Recent experimental observations have found that unconventional superconductors behave like strange metals, where resistivity has a strictly linear relationship with temperature. 4,5 Additionally, there is a common scaling relationship between the superconducting transition temperature T c and the linear-in-T scattering coefficient A 1 , T c B A 1 0.5 , 6,7 which holds true for copper oxides, iron-based superconductors like Ba(Fe 1Àx Co x ) 2 As 2 and FeSe, and organic superconductors like (TMTSF) 2 PF 6 . 8 The parameter A 1 comes from the empirical equation r = r 0 + A 1 T with r as the resistivity, regressed with experimental data.…”

“…Excited by the common scaling relationships between T c and A 1 and the superfluid density observed among different types of superconductors, 6,7,9 we believe that our previously developed conductivity and superconductivity equations, which are not specific to any particular material, may provide some insight into this universal scaling phenomenon. Therefore, in this article we mathematically derive T c based on our previously developed conductivity equations to see if a similar scaling relationship can be predicted.…”