Itinerant spin excitations near the hidden order transition in URu2Si2

Abstract

By means of neutron scattering we show that the high-temperature precursor to the hidden order state of the heavy fermion superconductor URu${}_2$Si${}_2$ exhibits heavily damped incommensurate paramagnons whose strong energy dispersion is very similar to that of the long-lived longitudinal f-spin excitations that appear below T${}_0$. Since the underlying local f-exchange is preserved we expect only the f-d interactions to change across the phase transition and to cause the paramagnetic damping. The damping exhibits single-ion behavior independent of wave vector and vanishes below the hidden order transition. We suggest that this arises from a transition from valence fluctuations to a hybridized f-d state below T${}_0$. Here we present evidence that the itinerant excitations, like those in chromium, are due to Fermi surface nesting of hole and electron pockets so that the hidden order phase likely originates from a Fermi-surface instability. We identify wave vectors that span nested regions of a band calculation and that match the neutron spin crossover from incommensurate to commensurate on approach to the hidden order phase.

4 pages, 4 figures, to be submitted to PRL

References in corpus (5)

• Gapped itinerant spin excitations account for missing entropy in the hidden order state of URu${}_2$Si${}_2$
• Dynamic Stripes and Resonance in the Superconducting and Normal Phases of YBa2Cu3O6.5 Ortho-II Superconductor
• Helicity Order: Hidden Order Parameter in URu${}_2$Si${}_2$
• Competing Ordered Phases in URu2Si2: Hydrostatic Pressure and Re-substitution
• Itinerancy and Hidden Order in $UR{u}_{2}S{i}_2$

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• The modulated spin liquid: a new paradigm for URu${}_2$Si${}_2$
• Momentum-resolved evolution of the Kondo lattice into 'hidden-order' in URu2Si2
• Complex Landau Ginzburg Theory of the Hidden Order in URu_2Si_2
• Field-induced spin-density wave beyond hidden order in URu2Si2
• Incommensurate spin resonance in URu2Si2
• Symmetry and correlations underlying Hidden Order in URu2Si2
• Chemical pressure tuning of URu${}_2$Si${}_2$ via isoelectronic substitution of Ru with Fe
• Hybridization gap and anisotropic far-infrared optical conductivity of URu2Si2
• Hidden order pseudogap in URu${}_2$Si${}_2$
• High-magnetic field lattice length changes in URu2Si2
• Isoelectronic perturbations to $f$-$d$-electron hybridization and the enhancement of hidden order in URu${}_2$Si${}_2$
• Nuclear magnetic resonance studies of pseudospin fluctuations in URu${}_2$Si${}_2$
• Detailed optical spectroscopy of the hybridization gap and the hidden order transition in high quality URu${}_2$Si${}_2$ single crystals
• Inelastic x-ray scattering measurements on URu2Si2
• Neutron Scattering Study of URu${}_{2-x}$Re${}_x$Si${}_2$ with $x$ = 0.10: Driving Order towards Quantum Criticality
• 29Si nuclear magnetic resonance study of URu2Si2 under pressure