Ion beam generated surface ripples: new insight in the underlying mechanism

TL;DR

This paper introduces a novel hydrodynamic mechanism for ion beam surface patterning, emphasizing saltation and creep processes coupled with solid flow in the amorphous layer, offering new insights beyond traditional erosion-based models.

Contribution

It proposes a new mechanism involving solid flow and material transport at the amorphous/crystalline interface, supported by experiments and simulations, advancing understanding of ripple formation.

Findings

Saltation and creep processes influence ripple formation.

Solid flow controls ripple wavelength.

Material transport affects ripple amplitude.

Abstract

A new hydrodynamic mechanism is proposed for the ion beam induced surface patterning on solid surfaces. Unlike the standard mechanisms based on the ion beam impact generated erosion and mass redistribution at the free surface (proposed by Bradley-Harper (BH) and its extended theories), the new mechanism proposes that the ion beam induced saltation and creep processes, coupled with incompressible solid flow in amorphous layer, leads to the formation of ripple patterns at the amorphous/crystalline (a/c) interface and hence at the free surface. Ion beam stimulated solid flow inside the amorphous layer controls the wavelength, where as the amount of material transported and re-deposited at a/c interface control the amplitude of ripples. The new approach is verified by designed experiments and supported by the discrete simulation method.