engleski

Suppression of the charge-density wave state in Sr14Cu24O41 by calcium doping

The charge response in the spin chain and/or ladder compound Sr 14 -x Ca x Cu 24 O 41 is characterized by dc resistivity, low-frequency dielectric spectroscopy and optical spectroscopy. We identify a phase transition below which a charge-density wave (CDW) develops in the ladder arrays. Calcium doping suppresses this phase with the transition temperature decreasing from 210 K for x= 0 to 10 K for x= 9 , and the CDWgap from 130 meV down to 3 meV, respectively. This suppression is due to the worsened nesting originating from the increase of the interladder tight-binding hopping integrals, as well as from disorder introduced at the Sr sites. These results altogether speak in favor of two-dimensional super-conductivity under pressure.

charge density wave; superconductivity; dielectric response; optical response

nije evidentirano