Dispersion of a single $4f$ impurity state in photoemission spectra of Yb/W(110)

TL;DR

This study investigates the energy dispersion of a single Yb 4f impurity in photoemission spectra, revealing hybridization effects with W bands that depend on momentum, indicating impurity behavior rather than lattice periodicity.

Contribution

It demonstrates that the dispersion of Yb 4f states arises from k-dependent impurity interactions, not from periodic lattice effects, providing new insight into impurity states in surface spectra.

Findings

Yb 4f states show energy splitting and dispersion due to hybridization.

Dispersion occurs at specific points in the surface Brillouin zone.

Impurity behavior explains the observed spectral features.

Abstract

Angle-resolved photoemission spectra of a monolayer of Yb on W(110) reveal energy splittings and dispersion of the Yb 4f states that are obviously due to their hybridization with W-derived valence bands. These effects occur at well defined points of the surface Brillouin zone although a smearing over reciprocal space is expected from the structural incoherence of the Yb and W lattices. We conclude therefore that dispersion is not related to the periodic arrangement of the $4f$ states but reflects the k-dependent interaction of a single Yb 4f impurity with W bands.