Impact of STM tip on coarsening of In atomic chains on Si(100): A kinetic Monte Carlo study

Using a Kinetic Monte Carlo approach, we investigate the potential influence of STM tip on nucleation and subsequent growth of single-atom wide In chains on Si(100) during room-temperature deposition. Specifically, we examine the effect of repeated scanning on the stability of odd-size chains, as well as coarsening of chains in the post-deposition regime. In our simulations, the effects of the strong field developed between the STM tip and the positively charged In adsorbates when the sample is positively (negatively) biased are modeled by slightly lowering (raising) the activation barriers of adatoms directly underneath the tip. Evidence of stochastic ripening – a coarsening mechanism relying on a series of adatom exchanges between adjacent islands in one-dimensional systems and not driven by a difference in the chemical potential – will be presented. Finally, we will show that coarsening may be disrupted by STM tip effects.