Unified theory of superconductivity in La2-xSrxCuO4 and Sr2RuO4

This paper derives a generic Tc formula by using the long-range phase coher ence condition in quantum phase fluctuation of the order parameter. Taking the two-local-spin-mediated interaction as a Cooper pair potential, and usi ng BCS gap equation and the Tc formula, this paper explains some basic expe rimental findings of both the high-T-c singlet and the low-T-c triplet supe rconductors, i.e. La2-xSrCuO4 (LSCO) and Sr2RuO4 and predicts that the high -T-c superconductivity should also be discovered for extra-underdoped LSCO. (C) 2001 Published by Elsevier Science B.V.