Anomalous isotope effect and Van Hove singularity in superconducting Cu oxides

C. C. Tsuei; D. M. Newns; C. C. Chi; P. C. Pattnaik

doi:10.1103/PhysRevLett.65.2724

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Anomalous isotope effect and Van Hove singularity in superconducting Cu oxides

C. C. Tsuei, D. M. Newns, C. C. Chi, P. C. Pattnaik

DOI 10.1103/PhysRevLett.65.2724 · Physical Review Letters

T1

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Abstract

High-Tc Cu oxides such as YBa2Cu3O7 and the Bi-Sr-Ca-Cu-O systems are characterized by a near-zero oxygen-isotope effect. Recent results by Crawford et al. show, however, that the isotope effect in the La2−xSrxCuO4 system depends strongly on the doping level (x) and can significantly exceed the BCS limit. Within the framework of the BCS phonon-mediated pairing, a logarithmic (2D) Van Hove singularity in the density of states can provide a basis for understanding these anomalous isotope effects and possibly the origin of high-temperature superconductivity.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
YBa2Cu3O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
La2-xSrxCuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown