Figure 9.

(a) 3D representation of a constant current STM image ($I=1$ nA, $V=1$ mV, $4\times 5$ nm${}^2$) of a single Pt atom adsorbed on a Pt(111) surface and a schematic of the probing tip. (b) Time-average junction conductance $G_{av}=I_{av}/V$ (blue dashed curve) and frequency shift $\Delta f$ on top (black curve) and off (green curve) the Pt atom measured at different tip–sample distances d. The lower panel shows the dissipation signal D on top of the Pt atom recorded simultaneously with $G_{av}$ and $\Delta f$. (c) Calculated short-range force between tip apex and Pt adatom (full line) and simulated forces (squares) from data in (b). (d) Conductance after deconvolution of the tip oscillation (full line) and simulated conductance (squares). All conductances are given in units of the single–channel, spin–degenerate quantum of conductance $G_0=2e^2/h\approx {(\mathrm{12,906}\Omega )}^{-1}$ where e is the elementary charge and h is Planck’s constant. Adapted with permission from American Physical Society from Figure 1 in [46].