Single-particle excitation gap in La2−xSrxCuO4 studied by high-resolution angle-resolved photoemission

✍ Scribed by Y.X. Xiao; T. Sato; K. Terashima; H. Matsui; T. Takahashi; M. Kofu; K. Hirota

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 225 KB
• Volume: 463-465
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2007.03.434

✦ Synopsis

We report angle-resolved photoemission spectroscopy on optimally doped high-T c superconductor La 1.85 Sr 0.15 CuO 4 (T c = 37 K) to elucidate the character of low-energy excitations in the superconducting state. We find a clear evidence for the emergence of a sharp superconducting quasiparticle peak below T c together with opening of a superconducting gap at off-nodal region, while no signature of a quasiparticle peak is observed at (p, 0). From the comparison of spectral lineshape and energy dispersion between the nodal and the off-nodal region, we conclude that there are two characteristic energy scales (70 and 20 meV) in the superconducting state of optimally doped La 1.85 Sr 0.15 CuO 4 .