High-Tc Phase Diagram (IMAGE) DOE/Lawrence Berkeley National Laboratory Caption In this phase diagram common to many cuprate superconductors, the insulating phase typical of undoped cuprate compounds appears at the far left (black). Other phases appear with increased hole doping -- the dome-shaped superconducting phase below Tc (blue), the mysterious pseudogap below T* (red), and a “normal metallic” phase (white). New evidence from studies of Bi2201 (crystal structure inset) along the temperature range shown in greeen strongly supports the idea that the pseudogap is in fact a distinct phase of matter that persists into the superconducting phase. If so the T* phase transition must terminate in a quantum critical point (Xc) at zero temperature. Credit Ruihua He, Lawrence Berkeley National Laboratory Usage Restrictions with credit as given License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.