2007/01/28 by C. R. Wiebe, J. A. Janik, J.A. Janik +16 · 10 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Condensed matter physics #Electron #Excitation #Fermion #Inelastic neutron scattering #Magnetism #Neutron #Neutron scattering #Phase transition #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Rare-earth and actinide compounds #Spin (aerodynamics) #Superconductivity #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1038/nphys522
published as Nature Physics 3, 1 (2007) · 9 pages, 5 figures, high quality images available from Nature Replaced document with fixed figures
openalex publication_date 2007/01/28 · arxiv created 2007/10/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
One of the primary goals of modern condensed matter physics is to elucidate the nature of the ground state in various electronic systems. Many correlated electron materials, such as high temperature superconductors, geometrically frustrated oxides, and low-dimensional magnets are still the objects of fruitful study because of the unique properties which arise due to poorly understood many-body effects. Heavy fermion metals - materials which have high effective electron masses due to these effects - represent a class of materials with exotic properties, such as unusual magnetism, unconventional superconductivity, and "hidden order" parameters. The heavy fermion superconductor URu2Si2 has held the attention of physicists for the last two decades due to the presence of a "hidden order" phase below 17.5 K. Neutron scattering measurements indicate that the ordered moment is 0.03 μB, much too small to account for the large heat capacity anomaly at 17.5 K. We present recent neutron scattering experiments which unveil a new piece of this puzzle - the spin excitation spectrum above 17.5 K exhibits well-correlated, itinerant-like spin excitations up to at least 10 meV emanating from incommensurate wavevectors. The gapping of these excitations corresponds to a large entropy release and explains the reduction in the electronic specific heat through the transition.