Finding microscopic models for metallic states that exhibit quantum critical properties such as ω/T scaling is a major theoretical challenge. We calculate the local dynamical spin susceptibility χ(T,ω) for a Hubbard model at half filling using Dynamical Mean-Field Theory, which is exact in infinite dimensions. Qualitatively distinct behavior is found in the different regions of the phase diagram: Mott insulator, Fermi liquid metal, bad metal, and a quantum critical region above the finite temperature critical point. The signature of the latter is ω/T scaling where T is the temperature. Our results are consistent with previous results showing scaling of the dc electrical conductivity and are relevant to experiments on organic charge transfer salts.
@article{arxiv.1611.01822,
title = {Quantum critical local spin dynamics near the Mott metal-insulator transition in infinite dimensions},
author = {Nagamalleswararao Dasari and N. S. Vidhyadhiraja and Mark Jarrell and Ross H. McKenzie},
journal= {arXiv preprint arXiv:1611.01822},
year = {2017}
}