Imaging the coupling between itinerant electrons and localised moments in the centrosymmetric skyrmion magnet GdRu2Si2

TL;DR

This study uses spectroscopic-imaging scanning tunnelling microscopy to observe how itinerant electrons interact with localised magnetic moments in GdRu2Si2, revealing insights into skyrmion formation in centrosymmetric materials.

Contribution

It demonstrates the coupling between itinerant electrons and localised moments in GdRu2Si2 and links this to skyrmion stabilization mechanisms in inversion-symmetric compounds.

Findings

Patterns in local density of states vary with magnetic structures

Model calculations reproduce observed patterns

Provides clues to skyrmion formation mechanism

Abstract

Magnetic skyrmions were thought to be stabilised only in inversion-symmetry breaking structures, but skyrmion lattices were recently discovered in inversion symmetric Gd-based compounds, spurring questions of the stabilisationmechanism. A natural consequence of a recent theoretical proposal, a coupling between itinerant electrons and localised magnetic moments, is that the skyrmions are amenable to detection using even non-magnetic probes such as spectroscopic-imaging scanning tunnellingmicroscopy (SI-STM). Here SI-STM observations of GdRu$_2$Si$_2$ reveal patterns in the local density of states that indeed vary with the underlying magnetic structures. These patterns are qualitatively reproduced by model calculations which assume exchange coupling between itinerant electrons and localised moments. These findings provide a clue to understand the skyrmion formation mechanism in GdRu$_2$Si$_2$.