N.D. Lang, A.R. Williams
Physical Review B
In order to determine how the sample density of states is reflected in topographic images obtained in the scanning tunneling microscope, the apparent size of an adsorbed atom is studied as a function of bias voltage for several different atoms. This quantity is found to reflect state-density features that lie well above the Fermi level, but it shows a striking absence of any trace of d-state peaks below the Fermi level. © 1986 The American Physical Society.