Potential parent compound of superconductor: Sr2CuM2As2O2 (M = Mn, Fe)

The electronic structure of Sr2CuMn2As2O2 and Sr2CuFe2As2O2 are studied by the first-principle calculations. These compounds have a body-centered-tetragonal crystal structure that consists of the CuO2 layers similar to those in the high-TcTc cuprate superconductor, and intermetallic MAs (M = Mn, or Fe) layers similar to the FeAs layers in high-TcTc pnictides. Such special structure makes them as interesting candidates for new type of superconductor since they have two types of superconducting layers. However, our calculations indicate that the states in the range from −2.0 eV to +2.0 eV are dominated by Mn-3d or Fe-3d states, while the states of Cu-3d are far away from the Fermi level (in the range from −3.0 eV to −1.0 eV). Such results are significantly different with the Cu-based superconductor, like La2CuO4, where the states around Fermi level are dominated by Cu-3d states. Besides, we find that the mean-field magnetic ground state is the checkerboard antiferromagnetic in Cu sublattice and the stripe antiferromagnetic in Fe (or Mn) sublattice.