Substitution experiments on superconducting La2C2X2 (X = Cl, Br, I)

Article abstract of DOI:10.1002/zaac.19976230197

The layered carbide bromide La₂C₂Br₂ becomes superconducting at 6.2 K. We studied the matrix effect on T_c due to (isoelectronic) halogen substitution. T_c increases with the amount of substitution by chlorine to a maximum value of 7.2 K, and it decreases when Br^- is partially substituted by I^-. La₂C₂I₂ itself is non-superconducting down to 2 K. However, substitution of I^- by 10% Cl^- leads to superconductivity at 2.2 K.