STM STS STUDIES FOR DOPING EFFECTS ON THE SYMMETRY AND MAGNITUDE OF SUPERCONDUCTING GAP IN BI2SR2CACU2O8+DELTA/

Doping effects on the superconducting gap of BSCCO have been studied o ver a wide doping range from p-0.1 to 0.21, including the under-and ov erdoped crystals, by using STM/STS. The gap is consistent with d(x)2-( y)2 symmetry over the doping range examined. The gap magnitude 2 Delta (o), corresponding to the strength of pairing interaction, increases w ith decreasing p even in the underdoped region where T-c is largely re duced.