Revealing the correlation between real-space structure and chiral magnetic order at the atomic scale

TL;DR

This study combines advanced microscopy techniques and theoretical modeling to reveal how atomic-scale structural features influence chiral magnetic order in a buckled iron bilayer, providing insights into the structure-magnetism relationship.

Contribution

The paper introduces a novel SPEX imaging method that simultaneously captures geometric, electronic, and magnetic structures at the atomic level, linking surface reconstruction to magnetic order.

Findings

Reconstructed bilayer exhibits height corrugation linked to strain relaxation.

Chiral magnetic ground state identified in previously unobserved regions.

DFT calculations support experimental observations and identify favorable stoichiometry.

Abstract

We image simultaneously the geometric, electronic and magnetic structure of a buckled iron bilayer film that exhibits chiral magnetic order. We achieve this by combining spin-polarized scanning tunneling microscopy and magnetic exchange force microscopy (SPEX), to independently characterize the geometric as well as the electronic and magnetic structure of non-flat surfaces. This new SPEX imaging technique reveals the geometric height corrugation of the reconstruction lines resulting from strong strain relaxation in the bilayer, enabling the decomposition of the real-space from the eletronic structure at the atomic level, and the correlation with the resultant spin spiral ground state. By additionally utilizing adatom manipulation, we reveal the chiral magnetic ground state of portions of the unit cell that were not previously imaged with SP-STM alone. Using density functional theory (DFT), we investigate the structural and electronic properties of the reconstructed bilayer and identify the favorable stoichiometry regime in agreement with our experimental result.