# Subsurface diffusion in crystals and effect of surface permeability on the atomic step motion

## TL;DR

This paper presents a theoretical analysis of how surface permeability and point defect supersaturation influence atomic step motion and surface morphology dynamics in crystals.

## Contribution

It introduces a model incorporating a diffusive layer of bulk point defects to explain surface defect processes and their impact on step motion.

## Key findings

- Surface permeability affects atomic step rate.
- Point defect supersaturation controls surface morphology.
- Diffusive layer model explains defect dynamics.

## Abstract

Atomic mechanism of the bulk and surface point defect generation and annihilation on surface sinks is considered theoretically on the base of the Burton, Cabrera and Frank model. We show that the creation and annihilation of self-interstitials and vacancies at crystal surfaces can be described by introducing a diffusive layer of the bulk point defects adsorbed just below the surface. The effect of the surface permeability on the atomic step rate advance is analyzed. We conclude that the surface permeability, as well as the supersaturation of point defects in both gas and bulk phases, control the dynamic of the crystal surface morphology.