Electric Field-Induced Formation of a 2D Adatom Gas on Cryogenic Li Surfaces

TL;DR

This study uses DFT calculations to show that high electrostatic fields can induce the formation of a 2D adatom gas on lithium surfaces, explaining phenomena in atom probe tomography and electrochemical systems.

Contribution

It reveals a critical electrostatic field threshold causing surface atom instability and adatom formation, advancing understanding of electric field effects on surfaces.

Findings

High electrostatic fields induce 2D adatom gases on Li surfaces.

Field reverses adsorption site stability, enabling barrierless diffusion.

Mechanisms explain experimental observations in atom probe tomography.

Abstract

Intense electrostatic fields, such as those able to break bonds and cause field-ion emission, can fundamentally alter the behaviour of atoms at and on the surface. Using density functional theory (DFT) calculations on the Li (110) surface under high electrostatic fields, we identify a critical field strength at which surface atoms occupying a kink site become thermodynamically unstable against adatom formation. This mechanism leads to the formation of a highly concentrated two-dimensional (2D) adatom gas on the surface. Moreover, the applied field reverses the stability of preferred adsorption sites, enabling barrierless diffusion of lithium atoms even well below the threshold required for field evaporation. The here identified mechanisms offer a unified explanation for experimental observations in atom probe tomography and for understanding high electric field phenomena in systems such as battery interfaces and electrochemical environments.