Effects of configurational disorder on adatom mobilities on TiAlN(001) surfaces

TL;DR

This study investigates how configurational disorder in TiAlN(001) surfaces affects adatom mobility, revealing that disorder significantly reduces Ti adatom mobility while having minimal impact on Al adatoms, using first-principles calculations.

Contribution

It provides a detailed first-principles analysis of how surface disorder influences adatom diffusion in TiAlN alloys, highlighting differential effects on Ti and Al adatoms.

Findings

Disorder dramatically reduces Ti adatom mobility.

Al adatom migration is minimally affected by disorder.

Surface disorder impacts phase stability and nanostructure evolution.

Abstract

We use metastable NaCl-structure Ti0.5Al0.5N alloys to probe effects of configurational disorder on adatom surface diffusion dynamics which control phase stability and nanostructural evolution during film growth. First-principles calculations were employed to obtain potential energy maps of Ti and Al adsorption on an ordered TiN(001) reference surface and a disordered Ti0.5Al0.5N(001) solid-solution surface. The energetics of adatom migration on these surfaces are determined and compared in order to isolate effects of configurational disorder. The results show that alloy surface disorder dramatically reduces Ti adatom mobilities. Al adatoms, in sharp contrast, experience only small disorder-induced differences in migration dynamics.