Tunneling electrons from the tip of a scanning tunneling microscope can be used to induce adatom hopping on Br-terminated [Formula presented] at low current and without voltage pulses. Hopping does not occur when electrons tunnel from a sample to a tip. The threshold energy is [Formula presented], and tunneling spectroscopy shows antibonding Si-Br states 0.8 eV above the Fermi level. Electron capture in these states is a necessary condition for hopping, but repulsive adsorbate interactions that lower the activation barrier are also required. Such interactions are strong near saturation for Br but are insufficient when the coverage is low or when Br is replaced by Cl.
ASJC Scopus subject areas
- Physics and Astronomy(all)