Linear response theory of activated surface diffusion with interacting adsorbates

TL;DR

This paper develops a linear response theoretical framework to analyze activated surface diffusion with interacting adsorbates, incorporating surface phonons and coverage effects, and applies it to simple and realistic atomic diffusion systems.

Contribution

It introduces a two-bath model for adsorbate interactions and derives classical and quantum formulas for diffusion, including realistic atomic surface diffusion scenarios.

Findings

Classical and quantum formulas for diffusion are derived.

Application to Na diffusion on Cu(001) surface demonstrates model effectiveness.

Quantum corrections to classical diffusion results are discussed.

Abstract

Activated surface diffusion with interacting adsorbates is analyzed within the Linear Response Theory framework. The so-called interacting single adsorbate model is justified by means of a two-bath model, where one harmonic bath takes into account the interaction with the surface phonons, while the other one describes the surface coverage, this leading to defining a collisional friction. Here, the corresponding theory is applied to simple systems, such as diffusion on flat surfaces and the frustrated translational motion in a harmonic potential. Classical and quantum closed formulas are obtained. Furthermore, a more realistic problem, such as atomic Na diffusion on the corrugated Cu(001) surface, is presented and discussed within the classical context as well as within the framework of Kramer's theory. Quantum corrections to the classical results are also analyzed and discussed.