Abstract
Using high-resolution angle-resolved photoemission spectroscopy on we observe a new mass renormalization or “kink” in the E vs dispersion relations localized near The resolution of bilayer splitting allowed the first direct measurements of this interaction effect. The kink is clearly stronger than the kink observed along the nodal direction, appears at a lower energy (near 40 meV for overdoped samples), and is only apparent in the superconducting state. The kink energy scale defines a cutoff below which well-defined quasiparticle excitations occur. The most likely origin of this effect is coupling to the magnetic-resonance mode observed in inelastic neutron scattering.
- Received 8 April 2003
DOI:https://doi.org/10.1103/PhysRevB.68.174520
©2003 American Physical Society