Abstract
Laser-based angle-resolved photoemission measurements with superhigh resolution have been carried out on an optimally doped high temperature superconductor. New high energy features at and , in addition to the prominent one, are found to develop in the nodal electron self-energy in the superconducting state. These high energy features, which cannot be attributed to electron coupling with single phonon or magnetic resonance mode, point to the existence of a new form of electron coupling in high temperature superconductors.
- Received 19 December 2007
DOI:https://doi.org/10.1103/PhysRevLett.100.107002
©2008 American Physical Society