hide
Free keywords:
-
Abstract:
An attractive proposal for the hidden order (HO) in the heavy electron
compound URu2Si2 is an itinerant multipole order of high rank. It is due
to the pairing of electrons and holes centered on the zone center and
boundary, respectively, in states that have maximally different total
angular momentum components. Due to the pairing with a commensurate zone
boundary ordering vector the translational symmetry is broken and a HO
quasiparticle gap opens below the transition temperature T-HO. Inelastic
neutron scattering (INS) has demonstrated that for T < T-HO the
collective magnetic response is dominated by a sharp spin exciton
resonance at the ordering vector Q that is reminiscent of spin exciton
modes found inside the gap of unconventional superconductors and Kondo
insulators. We use an effective two-orbital tight-binding model
incorporating the crystalline-electric-field effect to derive closed
expressions for quasiparticle bands reconstructed by the multipolar
pairing terms. We show that the magnetic response calculated within that
model exhibits the salient features of the resonance found in INS. We
also use the calculated dynamical susceptibility to explain the
low-temperature NMR relaxation rate.
