Electron and hole doping in Nd-based cuprates with single-layer CuO2 sheets: Role of doped Ce ions and 30-K superconductivity

Yoshinori Tokura; Atsushi Fujimori; Hideki Matsubara; Hajime Watabe; Hidenori Takagi; Shinichi Uchida; Masayuki Sakai; Hiroshi Ikeda; Shigeru Okuda; Shoji Tanaka

doi:10.1103/PhysRevB.39.9704

Electron and hole doping in Nd-based cuprates with single-layer CuO2 sheets: Role of doped Ce ions and 30-K superconductivity

Yoshinori Tokura, Atsushi Fujimori, Hideki Matsubara, Hajime Watabe, Hidenori Takagi, Shinichi Uchida, Masayuki Sakai, Hiroshi Ikeda, Shigeru Okuda, Shoji Tanaka

DOI 10.1103/PhysRevB.39.9704 · Physical Review B

T1

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Abstract

We have attempted electron and hole doping in Nd-based cuprates with single-layer sheets of Cu-O squares and pyramids. It was found that partial substitution of Nd3+ sites with Ce4+ ions introduces mobile electrons into the Nd2CuO4 structure which shows two-dimensional (2D) sheets of Cu-O squares with no apical oxygens. With further Sr doping into Nd2−xCexCuO4, the crystalline lattice undergoes a structural transformation into the new hole-conductive compound with 2D sheets of Cu-O pyramids, which is identical with the superconducting phase discovered recently by Akimitsu et al. The hole concentration in Nd2−x−y CexSryCuO4−δ can be increased by controlling the composition (x,y) of non-copper cations and filling oxygen vacancies (δ) as well, which give rise to superconductivity with Tc up to 30 K.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Nd2-x-yCexSryCuO4-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	30	Pressure not reported	onset
Nd1.4Ce0.2Sr0.4CuO4-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	30	Pressure not reported	onset
Nd1.4Ce0.2Sr0.4CuO4-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	28	Pressure not reported	onset
Nd2-yCeSryCuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	20	Pressure not reported	unknown