Precise study of the resonance at Q0=(1,0,0) in URu2Si2

TL;DR

This study uses polarized inelastic neutron scattering to analyze the magnetic resonance at Q0 in URu2Si2, revealing a collective excitation and continuum in the hidden order phase with temperature-dependent behavior.

Contribution

It provides detailed experimental insights into the magnetic resonance and continuum at Q0 in URu2Si2, connecting these findings to theoretical models of the hidden order phase.

Findings

Magnetic resonance at E0 ≈ 1.7 meV appears below T0=17.8 K

Resonance energy shifts with temperature following an activation law

Resonance intensity exhibits BCS-like temperature dependence

Abstract

New inelastic neutron scattering experiments have been performed on URu2Si2 with special focus on the response at Q0=(1,0,0), which is a clear signature of the hidden order (HO) phase of the compound. With polarized inelastic neutron experiments, it is clearly shown that below the HO temperature (T0 = 17.8 K) a collective excitation (the magnetic resonance at E0 \approx 1.7 meV) as well as a magnetic continuum co-exist. Careful measurements of the temperature dependence of the resonance lead to the observation that its position shifts abruptly in temperature with an activation law governed by the partial gap opening and that its integrated intensity has a BCS-type temperature dependence. Discussion with respect to recent theoretical development is made.