Effect of doping on the pseudogap behaviour and the related terahertz modes in the hybrid chain-ladder compound, Sr14Cu24O41

Abstract

Using Terahertz (THz) spectroscopy, we report the observation of a pseudogap behaviour in the hybrid chain-ladder compound Sr14Cu24O41 (SCO). This is possibly due to the ordered arrangement of hole pairs in SCO's ladder plane, below the transition temperature, . Several optical modes in the THz frequency range between 60 cm−1 and 90 cm−1, similar to those reported earlier, was also observed. We find that the pseudogap behaviour and the THz-active modes are strongly affected by doping with 5% Co and 0.25% Al, but the effect of 1% Co is not as much. These differences are discussed in terms of the location of these dopants in the chain and ladder substructures.