Effect of Structural Supermodulation on Superconductivity in Trilayer Cuprate Bi2Sr2Ca2Cu3O10+δ

We investigate the spatial and doping evolutions of the superconducting properties of trilayer cuprate Bi2Sr2Ca2Cu3O10+delta by using scanning tunneling microscopy and spectroscopy. Both the superconducting coherence peak and gap size exhibit periodic variations with structural supennodulation, but the effect is much more pronounced in the underdoped regime than at optimal doping. Moreover, a new type of tunneling spectrum characterized by two superconducting gaps emerges with increasing doping, and the two-gap features also correlate with the supermodulation. We propose that the interaction between the inequivalent outer and inner CuO2 planes is responsible for these novel features that are unique to trilayer cuprates.