THE ISOTOPE EFFECT IN A SUPERLATTICE OF QUANTUM STRIPES

We have calculated the isotope effect coefficient and the critical tem perature in a particular superconducting heterostructure formed by a b idimensional (2D) superlattice of metallic quantum stripes. We model t he superlattice with a 2D free electron gas confined in a ID periodic potential barrier. Within the BCS theory we calculate the shape resona nce for the critical temperature and the isotope coefficient as a func tion of the chemical potential. The results provide a good description of the anomalous behavior of the isotope coefficient in La2-xSrxCuO4 as a function of doping with a sharp peak alpha similar to 0.8 in the underdoped regime and a rapid drop to alpha similar to 0.2 at 0.125 ho les per copper site.