Fermi surface manipulation by external magnetic field demonstrated for a prototypical ferromagnet

TL;DR

This study demonstrates that the Fermi surface of a prototypical ferromagnet, Fe(001), can be manipulated by external magnetic fields through spin-orbit coupling effects, revealing potential for electronic control in magnetic materials.

Contribution

It provides experimental evidence of magnetic field-induced Fermi surface manipulation via spin-orbit effects in a 3d ferromagnet, supported by first-principles calculations.

Findings

Magnetic field changes alter the Fermi surface by ~0.1 Å⁻¹

Spin-orbit induced band gaps of ~100 meV are observed

Bulk electronic states are influenced by surface symmetry effects

Abstract

We consider the details of the near-surface electronic band structure of a prototypical ferromagnet, Fe(001). Using high resolution angle-resolved photoemission spectroscopy we demonstrate openings of the spin-orbit induced electronic band gaps near the Fermi level. The band gaps and thus the Fermi surface can be manipulated by changing the remanent magnetization direction. The effect is of the order of $\Delta$E = 100 meV and $\Delta \text {k} = 0.1\,\text{\AA}^{-1}$. We show that the observed dispersions are dominated by the bulk band structure. First-principles calculations and one-step photoemission calculations suggest that the effect is related to changes in the electronic ground state, rather than caused by the photoemission process itself. The symmetry of the effect indicates that the observed electronic bulk states are influenced by the presence of the surface, which might be understood as related to a Rashba-type effect. By pinpointing the regions in the electronic band structure where the switchable band gaps occur, we demonstrate the significance of spin-orbit interaction even for elements as light as 3d ferromagnets.