arXiv:cond-mat/0403165 · Physical Review B
Crossover to non-Fermi-liquid spin dynamics in cuprates
J. Bonča, Peter Prelovšek, Igor Sega
Abstract
The antiferromagnetic spin correlation function ${S}_{\mathbf{Q}}$, the staggered spin susceptibility ${\ensuremath{\chi}}_{\mathbf{Q}}$, and the energy scale ${\ensuremath{\omega}}_{FL}={S}_{\mathbf{Q}}∕{\ensuremath{\chi}}_{\mathbf{Q}}$ are studied numerically within the $t\text{\ensuremath{-}}J$ model and the Hubbard model, as relevant to cuprates. It is shown that ${\ensuremath{\omega}}_{FL}$, related to the onset of the non-Fermi-liquid spin response at $T>{\ensuremath{\omega}}_{FL}$, is very low in the regime below the ``optimum'' hole doping ${c}_{h}<{c}_{h}^{*}\ensuremath{\sim}0.16$, while it shows a steep increase in the overdoped regime. A quantitative analysis of the NMR spin-spin relaxation rate $1∕{T}_{2G}$ for various cuprates reveals a similar behavior, indicating a pronounced crossover between a Fermi-liquid and a non-Fermi-liquid behavior as a function of doping.