Surface reconstruction induced Co Kondo resonance width modulation on one monolayer Ag covered Cu(111)

Abstract

We present a systematic study of the Kondo effect of single Co adatom placed on one monolayer (ML) Ag covered Cu(111) surface. The 1-ML Ag/Cu(111) shows apparent local density of states (LDOS) modulation which associated with the surface reconstruction. Interestingly, we find the Kondo resonance width of the Co adatom on 1-ML Ag/Cu(111) is position-dependent. When the Co adatom is placed near the triangular dislocation loop (hcp/fcc boundary), the Kondo resonance width is generally wider than the one measured at fcc site. At the fcc region, the measured Kondo resonance width is closely related to the LDOS variation. In conjunction with the tight binding approximation calculation, we identify that the main contribution of the LDOS modulation is the surface-reconstruction-regulated surface states. With a recently developed model, we further determine the contributions of the bulk and surface states to the Kondo resonance. These findings clarify the role of surface reconstruction on the Kondo effect.