STM Atom Manipulation: Assembling a Quantum Corral

Real scanning tunneling microscopes do more than image surfaces — lowering the tip into a "manipulation gap" a few ångströms above an adsorbed atom lets the tip-sample force drag that single atom sideways across the lattice, one hop at a time. This simulator renders a copper surface scattered with ten free adatoms and a ring of ten empty lattice sites. Drag the tip near an atom in pull mode, lower the gap below the manipulation threshold to grab it, and drag it onto an empty ring marker to lock it in place — the same lateral-manipulation technique Don Eigler and Erhard Schweizer used at IBM in 1990 to spell "IBM" with 35 xenon atoms. Live readouts track the exponential tunneling current I(V,d), the current imaging-vs-manipulation regime, and how many atoms you've locked into the corral.