1998/06/30 by Olivier Parcollet, Antoine Georges · 1 citation
Physics and Astronomy · #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.59.5341
40 pages, RevTeX, including 13 figures in EPS. v2 : minor changes, some references added
arxiv created 1998/08/20 · arxiv updated 2016/08/31
We study the doping of a Mott insulator in the presence of quenched frustrating disorder in the magnetic exchange. A low doping regime δ<J/t is found, in which the quasiparticle coherent scale is low : εF^* = J (δ/δ^*)2 with δ^*=J/t (the ratio of typical exchange to hopping). In the ``quantum critical regime'' εF^*<T<J, several physical quantities display Marginal Fermi Liquid behaviour : NMR relaxation time 1/T1∼ const., resistivity ρdc(T) ∝ T, optical lifetime τopt-1∝ ω/ln(ω/\epstar) and response functions obey ω/T scaling, e.g. J∑q χ''(q,ω) ∝ \tanh (ω/2T). In contrast, single-electron properties display stronger deviations from Fermi liquid theory in this regime with a √ω dependence of the inverse single-particle lifetime and a 1/√ω decay of the photoemission intensity. On the basis of this model and of various experimental evidence, it is argued that the proximity of a quantum critical point separating a glassy Mott-Anderson insulator from a metallic ground-state is an important ingredient in the physics of the normal state of cuprate superconductors (particularly the Zn-doped materials). In this picture the corresponding quantum critical regime is a ``slushy'' state of spins and holes with slow spin and charge dynamics responsible for the anomalous properties of the normal state.