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Resumo: According to early ideas of Mott and Anderson, however, the interaction-driven metal-insulator transition – the Mott transition – remains a sharp T=0 phase transition even in absence of any uniform ordering across the transition region. Should this phase transition be regarded as a quantum critical point? To address this question, here we examine [1-3] the phase diagram and transport properties of the maximally frustrated half-filled Hubbard model, in the framework of dynamical mean-field theory (DMFT). We identify a “quantum Widom line” (QWL) which defines the center of the corresponding quantum critical region associated with Mott metal-insulator transition in this model. The evolution of resistivity with temperature is then evaluated along trajectories following (parallel to) the QWL, producing a family of curves with characteristic “fan-like” shape, displaying remarkable scaling behavior characteristic of quantum criticality. Precisely such behavior was found both in very recent experiments on organic Mott systems, and earlier experiments on diluted two-dimensional electron

gases in silicon [3]. 

[1] H. Terletska, et al., Phys. Rev. Lett. 107, 026401 (2011). 

[2] J. Vucicevic, et al., preprint, arXiv1210.7201. 

[3] M. M. Radonjic, et al., Phys. Rev. B 85, 085133 (2012)