On the basis of the itinerant-localized duality theory of spin fluctuations, the puzzling aspects of the neutron scattering experiments in the normal state of high-Tc cuprates are clarified from a global point of view. The dynamical spin structure factor exhibits two different aspects depending on the energy transfer ω. At lower energies, ω < ωc, where ωc is the fermion coherence energy, the spectrum is coherent so that the characteristic scales for wavevector and energy are temperature dependent, while at higher energies, ω > ωc, the spectrum is incoherent so that those characteristic scales are temperature independent. The integrated weight of the coherent part of the spectrum exhibits the so-called "spin gap" behavior when the Fermi surface of the itinerant fermion is technically nested, even though there is no excitation gap in the spectrum at all.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering