Interplay between SDW and induced local moments in URu2Si2

TL;DR

This paper presents a theoretical model explaining the magnetic ordering in URu2Si2 as a coexistence of a spin-density wave and induced local moments, aligning well with experimental data.

Contribution

It introduces a novel two-order-parameter model for URu2Si2's magnetic phase, emphasizing the coexistence of SDW and local moments with the same symmetry.

Findings

The model reproduces the pressure phase diagram topology.

Derived field dependences match experimental measurements.

The scenario explains the small antiferromagnetic moments observed.

Abstract

Theoretical model for magnetic ordering in the heavy-fermion metal URu2Si2 is suggested. The 17.5K transition in this material is ascribed to formation of a spin-density wave, which develops due to a partial nesting between electron and hole parts of the Fermi surface and has a negligibly small form-factor. Staggered field in the SDW state induces tiny antiferromagnetic order in the subsystem of localized singlet-singlet levels. Unlike the other models our scenario is based on coexistence of two orderings with the same antiferromagnetic dipole symmetry.The topology of the pressure phase diagram for such a two order parameter model is studied in the framework of the Landau theory. The field dependences of the staggered magnetization and the magnon gap are derived from the microscopic theory and found to be in good quantitative agreement with experiment.