Stable non-Fermi liquid phase of itinerant spin-orbit coupled ferromagnets

TL;DR

This paper demonstrates that spin-orbit coupled ferromagnets can host a stable non-Fermi liquid phase due to strong coupling between Goldstone modes and electrons, providing a new platform for non-Fermi liquid physics.

Contribution

It introduces a stable non-Fermi liquid phase in spin-orbit coupled ferromagnets, contrasting with the typically masked non-Fermi liquids in related systems.

Findings

Non-Fermi liquid phase is stable in spin-orbit coupled ferromagnets.

Possible experimental realizations include Rashba electron gases and topological insulator surfaces.

The phase persists despite competing superconducting tendencies.

Abstract

Direct coupling between gapless bosons and a Fermi surface results in the destruction of Landau quasiparticles and a breakdown of Fermi liquid theory. Such a non-Fermi liquid phase arises in spin-orbit coupled ferromagnets with spontaneously broken continuous symmetries due to strong coupling between rotational Goldstone modes and itinerant electrons. These systems provide an experimentally accessible context for studying non-Fermi liquid physics. Possible examples include low-density Rashba coupled electron gases, which have a natural tendency towards spontaneous ferromagnetism, or topological insulator surface states with proximity-induced ferromagnetism. Crucially, unlike the related case of a spontaneous nematic distortion of the Fermi surface, for which the non-Fermi liquid regime is expected to be masked by a superconducting dome, we show that the non-Fermi liquid phase in spin-orbit coupled ferromagnets is stable.