Abstract
We have measured the room-temperature reflectivity spectra in the infrared and visible range (500–25 000 ) of (0≤x≤1) and (0≤y≤0.5) polished ceramics as a function of doping (x and y). We show that the intensity of the entire infrared spectrum increases with the hole doping level (x or y). When separated into a Drude contribution and a mid-infrared band, both contributions exhibit a correlated increase as holes are transferred into the conducting planes and are therefore argued to be related to free carriers. We note that recent simulations of the t-J model, studied as a function of hole doping, provide a consistent description of such a behavior.
- Received 23 July 1991
DOI:https://doi.org/10.1103/PhysRevB.45.8065
©1992 American Physical Society