Universal relationship betweenTcand the hole content inp-type cuprate superconductors

A critical analysis of experimental data reveals a universal relationship between ${\mathit{T}}_{\mathit{c}}$/${\mathit{T}}_{\mathit{c},\mathrm{m}\mathrm{a}\mathrm{x}}$ and hole content among the p-type high-${\mathit{T}}_{\mathit{c}}$ cuprate superconductors. Each individual compound is characterized by the value of its maximum ${\mathit{T}}_{\mathit{c}}$, ${\mathit{T}}_{\mathit{c},\mathrm{m}\mathrm{a}\mathrm{x}}$ while the variation of ${\mathit{T}}_{\mathit{c}}$/${\mathit{T}}_{\mathit{c},\mathrm{m}\mathrm{a}\mathrm{x}}$ with the hole content is independent of the compound considered. The universal curve is characterized by a plateau, rather than a parabold, with sharp bends at both sides. The ${\mathit{T}}_{\mathit{c}}$ versus hole content curve has a close relation to hole contents determined by ordered arrangements of holes in the two-dimensional ${\mathrm{CuO}}_2$ layer.