Superconducting Gap and Pseudogap in Heavily Underdoped Bi2212

The relationship between the pseudogap and superconducting gap in high temperature cuprate superconductors remains an outstanding issue. In this talk, we will present laser-based angle-resolved photoemission spectroscopy results on underdoped Bi2Sr2(Ca,Dy)Cu2O8 high temperature superconductor. The latest generation of ARPES system equipped with the narrow-bandwidth VUV laser and the time-of-flight (TOF) electron energy analyzer is utilized here, which enables us to have super-high energy resolution, high momentum resolution, and simultaneous coverage of two-dimensional momentum space. From detailed temperature dependence near the nodal and antinodal regions, we will discuss the relationship between the pseudogap and superconducting gap in the underdoped cuprate superconductors.