Vicinal surface growth: bunching and meandering instabilities

TL;DR

This paper investigates the morphological instabilities of crystal surfaces during growth, focusing on the competition between bunching and meandering, and provides insights into pattern formation and roughness evolution validated by experiments.

Contribution

It introduces a detailed analysis of the interplay between bunching and meandering instabilities in surface growth, including numerical simulations and experimental comparisons.

Findings

Roughness exponent varies from 1/2 to 1 across regimes

Transitions between bunching and meandering are common

Surface shapes match experimental observations

Abstract

The morphology of a growing crystal surface is studied in the case of an unstable two-dimensional step flow. Competition between bunching and meandering of steps leads to a variety of patterns characterized by their respective instability growth rates. The roughness exponent is shown to go from 1/2 to 1, between the pure bunching to the meandering regimes. Using numerical simulations, we observe that generically, a transition between the two regimes occurs. We find surface shapes and roughness time evolution in quantitative agreement with experiments.