R.P. Huebener, C.C. Tsuei
Cryogenics
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. © 1990 The American Physical Society.
R.P. Huebener, C.C. Tsuei
Cryogenics
C.C. Tsuei, J.R. Kirtley, et al.
Journal of Physics and Chemistry of Solids
D.M. Newns, C.C. Tsuei
PHONONS 2007
C.C. Tsuei, D.M. Newns, et al.
Physical Review Letters