Incommensurate spin resonance in URu2Si2

TL;DR

This paper explains the incommensurate spin resonance observed in URu2Si2 as a consequence of a hidden order gap, drawing parallels with resonance phenomena in high-Tc and heavy fermion superconductors.

Contribution

It proposes a particle-hole condensate model for the hidden order gap and predicts the behavior of spin susceptibility and resonance energy in URu2Si2.

Findings

Resonance energy scales with hidden order temperature as ω_res ≈ 4 k_B T_HO.

Spin resonance features are similar to those in high-Tc and heavy fermion superconductors.

The model predicts observable effects on neutron scattering and local density of states.

Abstract

We focus on inelastic neutron scattering in $URu_2Si_2$ and argue that observed gap in the fermion spectrum naturally leads to the spin feature observed at energies $\omega_{res} = 4-6 meV$ at momenta at $\bQ^* = (1\pm 0.4, 0,0)$. We discuss how spin features seen in $URu_2Si_2$ can indeed be thought of in terms of {\em spin resonance} that develops in HO state and is {\em not related} to superconducting transition at 1.5K. In our analysis we assume that the HO gap is due to a particle-hole condensate that connects nested parts of the Fermi surface with nesting vector $\bf{Q}^* $. Within this approach we can predicted the behavior of the spin susceptibility at $\bQ^*$ and find it to be is strikingly similar to the phenomenology of resonance peaks in high-T$_c$ and heavy fermion superconductors. The energy of the resonance peak scales with $T_{HO}$ $\omega_{res} \simeq 4 k_BT_{HO}$. We discuss observable consequences spin resonance will have on neutron scattering and local density of states.