Enhanced Superconductivity up to 43 K by P/Sb Doping of Ca1−xLaxFeAs2

The effects of isovalent doping on the superconducting transition temperature Tc in novel 112-type iron arsenide Ca1-xLaxFeAs2 were studied by conducting measurements of electrical resistivity rho and magnetization M. P or Sb doping strongly enhances Tc: P-doped Ca0.84La0.16FeAs2 and Sb-doped Ca0.85La0.15FeAs2 exhibited Tc of 41 and 43 K, respectively, while Ca0.85La0.15FeAs2 without P/Sb exhibited Tc = 35 K. These observations will give a hint for further enhancing Tc of rare-earth doped Ca-Fe-As systems.