Abstract
We have investigated the low-energy electronic structure of the heavy fermion superconductor by angle-resolved photoemission. We focus on the dispersion and the peak width of the prominent quasi-two-dimensional Fermi surface sheet at the corner of the Brillouin zone as a function of temperature along certain directions with a photon energy of . We find slight changes of the Fermi vector and an anomalous broadening of the peak width when the Fermi energy is approached. Additionally, we performed resonant angle-resolved photoemission spectroscopy experiments with . A flat -derived band is observed with a distinct temperature dependence and a -dependent spectral weight. These results, including both off- and on-resonant measurements, fit qualitatively to a two-level mixing model derived from the periodic Anderson model.
- Received 22 February 2007
DOI:https://doi.org/10.1103/PhysRevB.77.155128
©2008 American Physical Society