Link between Adatom Resonances and the Cu(111) Shockley Surface State

Abstract

Low-temperature scanning tunneling microscopy and spectroscopy at 7 K was used to assemble and characterize native adatom islands of successive size on the Cu(111) surface. Starting from the single adatom we observe the formation of a series of quantum states which merge into the well known two-dimensional Shockley surface state in the limit of large islands. Our experiments reveal a natural physical link between this fundamental surface property and the $s{p}_z$ hybrid resonance associated with the single $\mathrm{Cu}/\mathrm{Cu}(111)$ adatom.