RKKY Interaction and Intrinsic Frustration in Non-Fermi Liquid Metals

TL;DR

This paper investigates how non-Fermi liquid metals mediate longer-range, oscillatory RKKY interactions that enhance frustration, suppress magnetic order, and lead to complex phase transitions, explaining experimental glassy behaviors.

Contribution

It reveals that RKKY interactions in non-Fermi liquids are longer-range and oscillatory, significantly affecting magnetic frustration and phase transitions, with a novel connection to the Brazovskii model.

Findings

Longer-range RKKY interactions in non-Fermi liquids.

Enhanced magnetic frustration suppressing ordering temperature.

Potential for first-order transitions and glassy phases.

Abstract

We study RKKY interaction in non-Fermi liquid metals. We find that the RKKY interaction mediated by non-Fermi liquid metals can be of much longer range than for a Fermi liquid. The oscillatory nature of RKKY interaction thus becomes more important in non-Fermi liquids, and gives rise to enhanced frustration when the spins form a lattice. Frustration suppresses the magnetic ordering temperature of the lattice spin system. Furthermore, we find that the spin system with longer range RKKY interaction can be described by the Brazovskii model, where the ordering wavevector lies on a shell with constant radius. Strong fluctuations in such model lead to a first-order phase transition and/or glassy phase. This may explain some recent experiments where glassy behavior was observed in stoichiometric heavy fermion material close to a ferromagnetic quantum critical point.