Universal versus Material-Dependent Two-Gap Behaviors of the High-Tc Cuprate Superconductors: Angle-Resolved Photoemission Study of La2-xSrxCuO4.

摘要

We have investigated the doping and temperature dependences of the pseudogap and superconducting gap in the single-layer cuprate La2-xSrxCu04 by angle-resolved photoemission spectroscopy. The results clearly exhibit two distinct energy and temperature scales, namely, the gap around (7T in., 0) of magnitude 6 and the gap around the node characterized by the d-wave order parameter 60 , In comparison with Bi22l2 having higher Tc's, 60 is smaller, while 6* and T* are similar. This result suggests that 6* and T* are approximately material-independent properties of a single CU02 plane, in contrast to the material-dependent 60, representing the pairing strength.