Revised superconducting phase diagram of hole doped Na$_{x}$(H$_{3}$O)$_{z}$CoO$_{2}\cdot y$H$_{2}$O

C. J. Milne; D. N. Argyriou; A. Chemseddine; N. Aliouane; J. Veira; S. Landsgesell; D. Alber

doi:10.1103/PhysRevLett.93.247007

paper

Revised superconducting phase diagram of hole doped Na $_{x}$ (H $_{3}$ O) $_{z}$ CoO $_{2} \cdot y$ H $_{2}$ O

arXiv:cond-mat/0401273 · doi:10.1103/PhysRevLett.93.247007

Abstract

We have studied the superconducting phase diagram of \NaH\space as a function of electronic doping, characterizing our samples both in terms of Na content $x$ and the Co valence state. Our findings are consistent with a recent report that intercalation of \oxp\space ions into Na $_{x}$ CoO $_{2}$ , together with water, act as an additional dopant indicating that Na sub-stochiometry alone does not control the electronic doping of these materials. We find a superconducting phase diagram where optimal \Tc\space is achieved through a Co valence range of 3.24 - 3.35, while \Tc\space decreases for materials with a higher Co valence. The critical role of dimensionality in achieving superconductivity is highlighted by similarly doped non-superconducting anhydrous samples, differing from the superconducting hydrate only in inter-layer spacing. The increase of the interlayer separation between CoO $_{2}$ sheets as Co valence is varied into the optimal \Tc\space region is further evidence for this criticality.

arXiv commentPaper updated on 29/10/2004, 4 pages, 4 figures. Physical Review Letters (in press)

Revised superconducting phase diagram of hole doped Na $_{x}$ (H $_{3}$ O) $_{z}$ CoO $_{2} \cdot y$ H $_{2}$ O

Abstract

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Revised superconducting phase diagram of hole doped Nax​(H3​O)z​CoO2​⋅yH2​O

Abstract

References in corpus (8)

Cited by in corpus (36)

Revised superconducting phase diagram of hole doped Na $_{x}$ (H $_{3}$ O) $_{z}$ CoO $_{2} \cdot y$ H $_{2}$ O