Role of doping, pressure and van Hove singularities on highest Tc materials

A review of some striking prdictions of electronic structure theory about the role of van Hove singularities (vHs) on the electronic structure and properties of the newest and highest temperature superconducting cuprates is given. The results provide possible strong evidence for the role of vHs in the superconductivity of quasi-2D high Tc systems. They thus serve to call attention to their role not only enhancing Tc through large increases in N(EF) and Fermi surface areas, but also in possibly providing support for vHs based excitonic pairing mechanisms for superconductivity. Further, this information, derived from the understanding - expressed as an empirical rule -gained from the related role of doping and pressure, is used to investigate other likely systems for being made into high Tc superconductors