Figure 4: 3D universal phase diagram of the superconducting critical temperature of cuprates. The values of color plot of the superconducting transition temperature go from 0 (black) to 135 K (white). The misfit strain (i.e., microstrain or internal chemical pressure) and the doping are normalized to the critical values of the 1/8 phase ; therefore the critical point is at (1, 1) where the superconducting critical temperature goes to zero (black). The maximum of the critical temperature occurs at (1.4, 0.5), that is, at doping 0.16 and misfit strain 0.35.