Author: ["Guangyong Xu","G. D. Gu","M. Hücker","B. Fauqué","T. G. Perring","L. P. Regnault","J. M. Tranquada"]
CITE.CC academic search helps you expand the influence of your papers.
Abstract
A systematic neutron-scattering study of large near-optimally doped single crystals of the cuprate superconductor, Bi2Sr2CaCu2O8+δ, indicates that its magnetic properties are governed by localized magnetic moments, and not by itinerant quasiparticles, as widely expected. Much of what we know about the electronic states of high-temperature superconductors is due to photoemission1,2,3 and scanning tunnelling spectroscopy4,5 studies of the compound Bi2Sr2CaCu2O8+δ. 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 cuprates6,7,8,9. 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 electrons10,11,12,13,14. Here, we present the first measurements of the magnetic spectral weight of optimally doped Bi2Sr2CaCu2O8+δ 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 (ref. 15), where quasiparticles16 and local moments17 coexist.Cite this article
Xu, G., Gu, G., Hücker, M. et al. Testing the itinerancy of spin dynamics in superconducting Bi2Sr2CaCu2O8+δ. Nature Phys 5, 642–646 (2009). https://doi.org/10.1038/nphys1360 