Electronic Energy Levels in High-Temperature Superconductors

Kurzfassung

Parent materials of high-temperature superconductors (HTSC) need to be doped to become superconducting. The optimum doping for maximum critical transition temperature Tc has been analyzed for more than 20 materials. Assuming a uniform doping distribution the distance x between doped unit cells—projected into the CuO2 plane for cuprates—shows a strong linear correlation to the inverse of Tc in the form (2x)**2=m1*1/Tc with a slope of m1=(2.786±0.029)×10E−15 [m**2* K]. The mercury cuprate homologous series HgBa2Ca{n−1}Cu{n} O{2n+2+δ} with n=1,2,3 has been used to demonstrate the procedure deriving the doping distance x from the optimum doping value δ.