Instability of the ferromagnetic quantum critical point in strongly interacting 2D and 3D electron gases with arbitrary spin-orbit splitting

TL;DR

This paper demonstrates that in strongly interacting 2D and 3D electron gases with spin-orbit splitting, resonant scattering processes destabilize the ferromagnetic quantum critical point, leading to a first-order phase transition.

Contribution

It reveals that such resonant processes cannot be suppressed by spin-orbit splitting and always destabilize the ferromagnetic quantum critical point, a novel insight in the field.

Findings

Resonant scattering processes destabilize the ferromagnetic quantum critical point.

The transition is always first-order due to these processes.

Spin susceptibility exhibits non-analytic behavior near the transition.

Abstract

In this work we revisit itinerant ferromagnetism in 2D and 3D electron gases with arbitrary spin-orbit splitting and strong electron-electron interaction. We identify the resonant scattering processes close to the Fermi surface that are responsible for the instability of the ferromagnetic quantum critical point at low temperatures. In contrast to previous theoretical studies, we show that such processes cannot be fully suppressed even in presence of arbitrary spin-orbit splitting. A fully self-consistent non-perturbative treatment of the electron-electron interaction close to the phase transition shows that these resonant processes always destabilize the ferromagnetic quantum critical point and lead to a first-order phase transition. Characteristic signatures of these processes can be measured via the non-analytic dependence of the spin susceptibility on magnetic field both far away or close to the phase transition.