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Itinerant spin excitations near the hidden order transition in URu2Si2



J. A. Janik, H. D. Zhou, Y.-J. Jo, L. Balicas, G. J. MacDougall, G. M. Luke, J. D. Garrett, K. J. McClellan, E. D. Bauer, J. L. Sarrao, Yiming Qiu, John R. Copley, Z. Yamani, W. J. Buyers, C. R. Wiebe


By means of neutron scattering we show that the high-temperature precursor to the hidden order state of the heavy fermion superconductor URu2Si2 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 T0. 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 T0. 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.
Journal of Physics: Condensed Matter


heavy fermion, spin excitation, inelastic neutron scattering


Janik, J. , Zhou, H. , Jo, Y. , Balicas, L. , MacDougall, G. , Luke, G. , Garrett, J. , McClellan, K. , Bauer, E. , Sarrao, J. , Qiu, Y. , Copley, J. , Yamani, Z. , Buyers, W. and Wiebe, C. (2009), Itinerant spin excitations near the hidden order transition in URu2Si2, Journal of Physics: Condensed Matter, [online], (Accessed April 15, 2024)
Created April 22, 2009, Updated March 21, 2024