Metallic Surface Reconstruction Driven by Frustrated Antiferromagnetism

TL;DR

This paper proposes that the honeycomb surface reconstruction on certain metallic surfaces is driven by frustrated antiferromagnetic interactions, leading to structural distortion and net magnetization at low temperatures.

Contribution

It introduces a magnetic mechanism for surface reconstruction driven by frustrated antiferromagnetism on a triangular lattice.

Findings

Reconstructed surfaces can exhibit net magnetization at low temperatures.

Structural distortion is linked to antiferromagnetic instability.

The model explains the honeycomb pattern in metallic surface reconstructions.

Abstract

A magnetic origin for the honeycomb reconstruction of metallic surfaces with three-fold symmetry like Pb/Ge (111) is proposed. Assuming that the groundstate is an antiferromagnetic insulator over the triangular lattice of adatom sites (Pb), we demonstrate that the former is simultaneously unstable to canting and to a structural distortion if the surface is soft enough. We therefore predict a net magnetization over the reconstructed surface at sufficiently low temperature.