Universal versus material-dependent two-gap behaviors of the high-Tc cuprate superconductors: angle-resolved photoemission study of La2-xSrxCuO4.
We have investigated the doping and temperature dependences of the pseudogap and superconducting gap in the single-layer cuprate La2-xSrxCuO4 by angle-resolved photoemission spectroscopy. The results clearly exhibit two distinct energy and temperature scales, namely, the gap around (pi, 0) of magnitude Delta* and the gap around the node characterized by the d-wave order parameter Delta0. In comparison with Bi2212 having higher Tc's, Delta0 is smaller, while Delta* and T* are similar. This result suggests that Delta* and T* are approximately material-independent properties of a single CuO2 plane, in contrast to the material-dependent Delta0, representing the pairing strength.
Yoshida
T
T
Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
Hashimoto
M
M
Ideta
S
S
Fujimori
A
A
Tanaka
K
K
Mannella
N
N
Hussain
Z
Z
Shen
Z-X
ZX
Kubota
M
M
Ono
K
K
Komiya
Seiki
S
Ando
Yoichi
Y
Eisaki
H
H
Uchida
S
S