Doping structure of the high temperature superconductor La_(2-Δ)Ca_(1+Δ)Cu_2O_(6+δ)

摘要

The double doped unit cell of La_(2-Δ)Ca_(1+Δ)Cu_2O_(6+δ) (LCCO-52) consists of two chemical formulas, La_2CaCu_2O_7 and Ca_3Cu_2O_6 which are responsible for the occurrence of superconductivity with n = 2 superconducting CuO_2 planes per chemical formula. The distance x between double doped unit cells projected into a CuO_2 plane matches the experimental transition temperature T_c quite well.