Fig. 5
From: Machine learning modeling of superconducting critical temperature
Scatter plots of Tc for superconducting materials in the space of significant, family-specific regression predictors. For 4000 “low-Tc” superconductors (i.e., non-cuprate and non-iron-based), Tc is plotted vs. the a average atomic weight, b average covalent radius, and c average number of d valence electrons. The dashed red line in a is \(\sim 1{\mathrm{/}}\sqrt {m_A}\). Having low average atomic weight and low average number of d valence electrons are necessary (but not sufficient) conditions for achieving high Tc in this group. d Scatter plot of Tc for all known superconducting cuprates vs. the mean number of unfilled orbitals. c, d suggest that the values of these predictors lead to hard limits on the maximum achievable Tc
