Insight into the electronic structure of the centrosymmetric skyrmion magnet GdRu2Si2

Insight into the electronic structure of the centrosymmetric skyrmion magnet GdRu₂Si₂†

S. V. Eremeev,

*^a D. Glazkova,^b G. Poelchen,

^c A. Kraiker,^d K. Ali,^e A. V. Tarasov,^bi S. Schulz,^c K. Kliemt,

^d E. V. Chulkov,

^bfgh V. S. Stolyarov,^ijk A. Ernst,

^l C. Krellner,

^d D. Yu. Usachov

^bik and D. V. Vyalikh

*^hm

Author affiliations

* Corresponding authors

^a Institute of Strength Physics and Materials Science, Russian Academy of Sciences, 634055 Tomsk, Russia
E-mail: eremeev@ispms.tsc.ru

^b St. Petersburg State University, 7/9 Universitetskaya Nab., St. Petersburg, Russia

^c Institut für Festkörper- und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany

^d Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, D-60438 Frankfurt am Main, Germany

^e Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, Sweden

^f Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco UPV/EHU, 20080 San Sebastián/Donostia, Spain

^g Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, 20018 San Sebastián/Donostia, Spain

^h Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
E-mail: denis.vyalikh@dipc.org

ⁱ Moscow Institute of Physics and Technology, Institute Lane 9, Dolgoprudny, Russia

^j Dukhov Research Institute of Automatics (VNIIA), Moscow, Russia

^k National University of Science and Technology MISIS, Moscow, Russia

^l Institute for Theoretical Physics, Johannes Kepler University, Linz, Austria

^m IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain

Abstract

The discovery of a square magnetic-skyrmion lattice in GdRu₂Si₂, with the smallest so far found skyrmion size and without a geometrically frustrated lattice, has attracted significant attention. In this work, we present a comprehensive study of surface and bulk electronic structures of GdRu₂Si₂ by utilizing momentum-resolved photoemission (ARPES) measurements and first-principles calculations. We show how the electronic structure evolves during the antiferromagnetic transition when a peculiar helical order of 4f magnetic moments within the Gd layers sets in. A nice agreement of the ARPES-derived electronic structure with the calculated one has allowed us to characterize the features of the Fermi surface (FS), unveil the nested region along k_z at the corner of the 3D FS, and reveal their orbital compositions. Our findings suggest that the Ruderman–Kittel–Kasuya–Yosida interaction plays a decisive role in stabilizing the spiral-like order of Gd 4f moments responsible for the skyrmion physics in GdRu₂Si₂. Our results provide a deeper understanding of electronic and magnetic properties of this material, which is crucial for predicting and developing novel skyrmion-based systems.