Scan-protocol dependence of anisotropy in STM-driven growth: Comparison of raster and single-leg scanning

Abstract

We investigate the role of scan protocol in STM-driven surface growth using a lattice-based kinetic Monte Carlo model with a localized, moving perturbation to adatom mobility. Three cases are considered: STM-off, full raster scanning, and a single-leg protocol in which the perturbation is applied only during one scan direction.

At fixed perturbation strength, both STM-on protocols produce anisotropic structures, while the STM-off case remains close to a constant baseline value. The magnitude of anisotropy depends on the scan protocol, with the single-leg case exhibiting stronger anisotropy at lower perturbation strengths. As the perturbation strength increases, a crossover in anisotropy is observed, indicating that scan protocol and energetic modulation jointly influence morphological evolution.