title: Suppression of the charge-density-wave state in Sr14Cu24O41 by calcium doping.
abstract: The charge response in the spin chain and/or ladder compound Sr14-xCaxCu24O41 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 CDW gap 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 superconductivity under pressure.
authors.affiliation: Institut za fiziku, P.O. Box 304, HR-10001 Zagreb, Croatia. tvuletic@ifs.hr
authors.forename: T
authors.initials: T
authors.lastname: Vuletić
authors.forename: B
authors.initials: B
authors.lastname: Korin-Hamzić
authors.forename: S
authors.initials: S
authors.lastname: Tomić
authors.forename: B
authors.initials: B
authors.lastname: Gorshunov
authors.forename: P
authors.initials: P
authors.lastname: Haas
authors.forename: T
authors.initials: T
authors.lastname: Rõõm
authors.forename: M
authors.initials: M
authors.lastname: Dressel
authors.forename: J
authors.initials: J
authors.lastname: Akimitsu
authors.forename: T
authors.initials: T
authors.lastname: Sasaki
authors.forename: T
authors.initials: T
authors.lastname: Nagata