Kinks near the Fermi level observed in angle-resolved photoemission spectroscopy (ARPES) have been widely accepted to represent electronic coupling to collective excitations, but kinks at higher energies have eluded a unified description. We identify the mechanism leading to such kink features by means of ARPES and tight-binding band calculations on σ bands of graphene, where anomalous kinks at energies as high as ∼4 eV were reported recently [Phys. Rev. Lett. 111, 216806 (2013)]. We found that two σ bands show a strong intensity modulation with abruptly vanishing intensity near the kink features, which is due to sublattice interference. The interference induced local singularity in the matrix element is a critical factor that gives rise to apparent kink features, as confirmed by our spectral simulations without involving any coupling to collective excitations.
Bibliographical noteFunding Information:
This work was supported by IBS-R014-D1. The ALS was supported by the U.S. Department of Energy, Office of Sciences, under Contract No. DE-AC02-05CH11231. We thank J. Denlinger and Y.K. Kim for help with experiments, and S.-H. Jhi, S.-H. Lee, and D. Cho for valuable discussions.
© 2016 American Physical Society.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)