Exotic quantum states and fractionalized magnetic excitations, such as spinons in one-dimensional chains, are generally expected to occur in 3d transition metal systems with spin 1/2. Our neutron-scattering experiments on the 4f-electron metal Yb2Pt 2 Pb overturn this conventional wisdom. We observe broad magnetic continuum dispersing in only one direction, which indicates that the underlying elementary excitations are spinons carrying fractional spin-1/2. These spinons are the emergent quantum dynamics of the anisotropic, orbital-dominated Yb moments. Owing to their unusual origin, only longitudinal spin fluctuations are measurable, whereas the transverse excitations such as spin waves are virtually invisible to magnetic neutron scattering. The proliferation of these orbital spinons strips the electrons of their orbital identity, resulting in charge-orbital separation.
|Number of pages||5|
|State||Published - Jun 3 2016|
Bibliographical noteFunding Information:
Work at Brookhaven National Laboratory (I.A.Z., A.M.T., M.S.K.) was supported by the Office of Basic Energy Sciences (BES), Division of Materials Sciences and Engineering, U.S. Department of Energy (DOE), under contract DE-SC00112704. Work at Stony Brook (L.S.W., W.J.G., M.C.A.) was supported by NSF-DMR-131008. L.S.W. was also supported by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory (ORNL). This research at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. DOE. Work at NIST Center for Neutron Research (NCNR) is supported in part by the NSF under Agreement no. DMR-1508249. J.-S.C. and M.B. acknowledge support from the Netherlands Organization for Scientific Research (NWO) and the Foundation for Fundamental Research on Matter (FOM) of the Netherlands.
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