![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
Angle-resolved photoemission experiments have been performed on USb2, and very narrow quasiparticle peaks have been observed in a band, which local spin-density approximation (LSDA) predicts to osculate the Fermi energy. The observed band is found to be depressed by 17 meV below the Fermi energy. Furthermore, the inferred quasiparticle dispersion relation for this band exhibits a kink at an energy of about 23 meV below the Fermi energy. The kink is not found in LSDA calculations and, therefore, is attributable to a change in the quasiparticle mass renormalization by a factor of approximately 2. The existence of a kink in the quasiparticle dispersion relation of a band that does not cross the Fermi energy is unprecedented. The kink in the quasiparticle dispersion relation is attributed to the effect of the interband self-energy, involving transitions from the osculating band into a band that does cross the Fermi energy.
Acknowledgements
The authors would like to thank James L. Smith for his friendship, support and encouragement over the years. The work at Temple University was supported by the US Department of Energy, Office of Basic Energy Sciences. Work at LANL was performed under the auspices of the US DOE and LANL LDRD Program. The SRC is supported by the NSF under Award Np. DMR-0084402. Support from the Swedish Research Council (VR), SNIC, and European Commission (JRC-ITU) is gratefully acknowledged. EG was supported by Polish grant N202 140 32/3877. Thanks are due to K. Byczuk, A. Kaminski, J.D. Thompson, F. Ronning, T. Klimczuk, C. Batista, A. Balatsky and Y.-F. Yang for stimulating discussions.