Thermodynamics of $T_{\mathrm{c}}$ suppression in far-overdoped Tl${}_2$Ba${}_2$CuO${}_6$

Abstract

The physical origin of the suppression of superconductivity with hole doping in overdoped cuprates remains unclear. We measure the electronic specific heat of microgram-scale Tl${}_2$Ba${}_2$CuO${}_6$ crystals and find sharp superconducting anomalies persisting far into the overdoped regime. A weak-coupling BCS-like framework incorporating the known Fermi surface and cation disorder quantitatively reproduces the observed anomalies for $T_{\mathrm{c}}=14$-$25$ K and their weak doping dependence. The results show $T_{\mathrm{c}}(p)$ to be driven predominantly by a smoothly decreasing pairing strength.