Superconducting coherence peak in the electronic excitations of a single-layer Bi2Sr1.6La0.4CuO6+δ cuprate superconductor

Angle resolved photoemission spectroscopy study is reported on a high quality optimally doped Bi2Sr1.6La0.4CuO6+delta high-T-c superconductor. In the antinodal region with a maximal d-wave gap, the symbolic superconducting coherence peak, which has been widely observed in multi-CuO2-layer cuprate superconductors, is unambiguously observed in a single-layer system. The associated peak-dip separation is just about 19 meV, which is much smaller than its counterparts in multilayered compounds, but correlates with the energy scales of spin excitations in single-layer cuprates.