Fermi-surface origin of skyrmion lattices in centrosymmetric rare-earth intermetallics

TL;DR

This paper demonstrates how specific Fermi surface features in centrosymmetric rare-earth intermetallics influence magnetic interactions, leading to skyrmion lattice formation, with results supported by first-principles calculations and spin-dynamics simulations.

Contribution

It reveals the Fermi surface origin of skyrmion lattices in centrosymmetric compounds, linking electronic structure to magnetic textures.

Findings

Fermi surface nesting determines exchange interactions.

Helical spin-spiral ground states match experimental data.

Skyrmion lattice stabilization is connected to Fermi surface topology.

Abstract

We show from first-principles that barrel-shaped structures within the Fermi surface of the centrosymmetric intermetallic compounds GdRu$_2$Si$_2$ and Gd$_2$PdSi$_3$ give rise to Fermi surface nesting, which determines the strength and sign of quasi-two-dimensional Ruderman-Kittel-Kasuya-Yosida pairwise exchange interactions between the Gd moments. This is the principal mechanism leading to their helical single-$q$ spin-spiral ground states, providing transition temperatures and magnetic periods in good agreement with experiment. Using atomistic spin-dynamic simulations, we draw a direct line between the subtleties of the three-dimensional Fermi surface topology and the stabilization of a square skyrmion lattice in GdRu$_2$Si$_2$ at applied magnetic fields as observed in experiment.