Atomic-scale perspective on the origin of attractive step interactions on Si(113)

TL;DR

This study investigates the atomic-scale origins of attractive interactions between steps on Si(113) surfaces, revealing that monopole annihilation at step edges causes short-range attraction, consistent with experimental observations.

Contribution

It provides a detailed atomic-scale explanation for the short-range attraction between steps on Si(113), linking force monopole interactions to step bunching phenomena.

Findings

Short-range attraction arises from monopole annihilation at step edges.

The calculated interaction energies match experimental data.

Step bunching is driven by a balance of long-range repulsion and short-range attraction.

Abstract

Recent experiments have shown that steps on Si(113) surfaces self-organize into bunches due to a competition between long-range repulsive and short-range attractive interactions. Using empirical and tight-binding interatomic potentials, we investigate the physical origin of the short-range attraction, and report the formation and interaction energies of steps. We find that the short-range attraction between steps is due to the annihilation of force monopoles at their edges as they combine to form bunches. Our results for the strengths of the attractive interactions are consistent with the values determined from experimental studies on kinetics of faceting.