Ferromagnetic Quantum Critical Point in Non-Centrosymmetric Systems

TL;DR

This paper proposes that non-centrosymmetric metals with strong spin-orbit coupling can host a ferromagnetic quantum critical point, overcoming previous challenges caused by soft modes in clean systems.

Contribution

It demonstrates that the absence of inversion symmetry and strong spin-orbit interaction suppress soft modes, enabling quantum criticality in ferromagnetic metals.

Findings

Non-centrosymmetric metals can realize ferromagnetic quantum critical points.

Spin-orbit interaction suppresses soft modes that hinder quantum criticality.

Absence of inversion symmetry prevents new soft modes from disrupting critical behavior.

Abstract

Ferromagnetic quantum criticality in clean metals has proven elusive due to fermionic soft modes that drive the transition first order. We show that non-centrosymmetric metals with a strong spin-orbit interaction provide a promising class of materials for realizing a ferromagnetic quantum critical point in clean systems. The spin-orbit interaction renders massive the soft modes that interfere with quantum criticality in most materials, while the absence of spatial inversion symmetry precludes the existence of new classes of soft modes that could have the same effect.