Madelung Strain in Cuprate Superconductors - A Route to Enhancement of the Critical Temperature

Madelung Strain in cuprate films containing metal (M = La1.56Sr0.44CuO4) and insulator (I = La2CuO4) layers: X-ray diffraction shows that, unexpectedly, the volume of unit cell of the top layer adjusts to that of the bottom layer. The effect is due to long-range Coulomb forces; it affects interfacial superconductivity because the critical temperature scales with the unit-cell height.