Electrodynamic properties of an artificial heterostructured superconducting cuprate

We perform infrared conductivity measurements on a series of {\mathrm{CaCuO}}_{2}\text{/}{\mathrm{SrTiO}}_{3}heterostructures made by the insulating cuprate {\mathrm{CaCuO}}_{2}(CCO) and the insulating perovskite {\mathrm{SrTiO}}_{3}(STO). We estimate the carrier density of various heterostructures with different levels of hole doping from the integral of the optical conductivity, and we measure the corresponding degree of correlation...