Theorists Take Steps Toward Understanding Ladder Compounds

Whatever causes superconductivity above 40 K, it seems to involve the layers containing copper and oxygen atoms, which are common to all compounds exhibiting a high critical temperature, $T_c.$ Hoping to gain insight into the mechanism for superconductivity in these complex structures, some theorists have looked at systems as simple as one‐dimensional chains of copper and oxygen atoms. More recently they have turned to copper oxide ladders—that is, pairs of copper oxide chains linked by additional oxygen atoms between the coppers. So far, the theorists have predicted a number of physical properties of such ladders, including the possibility that the ladders can go superconducting.