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Persistent URL http://purl.org/net/epubs/work/50812
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Record Id 50812
Title Testing the itinerancy of spin dynamics in superconducting Bi2Sr2CaCu2O8+
Abstract Much of what we know about the electronic states of high-temperature superconductors is due to photoemission and scanning tunnelling spectroscopy studies of the compound Bi2Sr2CaCu2O8+. The demonstration of well-defined quasiparticles in the superconducting state has encouraged many theorists to apply the conventional theory of metals, Fermi-liquid theory, to the cuprates. In particular, the spin excitations observed by neutron scattering at energies below twice the superconducting gap energy are commonly believed to correspond to an excitonic state involving itinerant electrons. Here, we present the first measurements of the magnetic spectral weight of optimally doped Bi2Sr2CaCu2O8+ in absolute units. The lack of temperature dependence of the local spin susceptibility across the superconducting transition temperature, Tc, is incompatible with the itinerant calculations. Alternatively, the magnetic excitations could be due to local moments, as the magnetic spectrum is similar to that in La1.875Ba0.125CuO4, where quasiparticles16 and local moments coexist.
Organisation ISIS , ISIS-MAPS , STFC
Keywords Physics
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Language English (EN)
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Journal Article Nature 5 (2009): 642-646. doi:10.1038/nphys1360 2009