Inversion-asymmetric itinerant antiferromagnets by the space group symmetry

TL;DR

This paper explores how inversion-asymmetric antiferromagnetic phases can emerge in nonsymmorphic systems with magnetic ions, emphasizing the role of symmetry, electronic band nesting, and anisotropy.

Contribution

It establishes the symmetry conditions and derives a Landau free energy framework for understanding inversion-asymmetric antiferromagnetism in itinerant systems.

Findings

Symmetry of Wyckoff positions influences magnetic order

Nesting properties of electronic bands are crucial

Anisotropy affects the stability of phases

Abstract

We investigate the appearance of an inversion-asymmetric antiferromagnetism due to an itinerant mechanism in nonsymmorphic systems with magnetic ions at Wyckoff position of multiplicity 2. The key symmetries which underpin the existence of such phases are established, and we derive a Landau free energy from a general microscopic electronic Hamiltonian. Our analysis reveals that the stable antiferromagnetic order is largely determined by the symmetries of Wyckoff position, the nature of the nesting between electronic bands, and the presence of anisotropy or nesting in high-symmetry planes of the Brillouin zone. We illustrate our conclusions with specific microscopic models.