Observation of a kink in the dispersion of f-electrons

¹  Los Alamos National Laboratory - Los Alamos, NM 87545, USA
²  Department of Physics, Temple University - Philadelphia, PA 19122, USA
³  Ames Laboratory, Iowa State University - Ames, IA 50011, USA
⁴  Department of Physics and Materials Science, Uppsala University - Box 530, S-75121 Uppsala, Sweden, EU
⁵  Institute of Physics, Polish Academy of Sciences - 02-668 Warsaw, Poland, EU
⁶  Lawrence Livermore National Laboratory - Livermore, CA 94550, USA

Corresponding author: tomasz@lanl.gov

Received: 10 July 2008
Accepted: 15 September 2008

Abstract

Strong interactions in correlated electron systems may result in the formation of heavy quasiparticles that exhibit kinks in their dispersion relation. Spectral weight is incoherently shifted away from the Fermi energy, but Luttinger's theorem requires the Fermi volume to remain constant. Our angle-resolved photoemission study of USb₂ reveals a kink in a noncrossing band, representing the first experimental observation of a kink structure in f-electron systems. The kink energy scale of 21 meV and the ultra-small peak width of 3 meV are observed. We propose the novel mechanism of renormalization of a point-like Fermi surface, and that Luttinger's theorem remains applicable.