Charge and spin criticality for the continuous Mott transition in a two-dimensional organic conductor

TL;DR

This study investigates the critical behavior of charge and spin during the continuous Mott transition in a two-dimensional organic conductor, revealing the importance of short-range correlations and aligning with experimental observations.

Contribution

It demonstrates the critical scaling of charge and spin in a 2D Hubbard model using cluster DMFT, highlighting deviations from simple universality classes due to nonlocal correlations.

Findings

Charge transition is smoother than Ising predictions.

Spin susceptibility matches NMR measurements.

Short-range correlations significantly influence critical behavior.

Abstract

We study the continuous bandwidth-controlled Mott transition in the two-dimensional single-band Hubbard model with a focus on the critical scaling behavior of charge and spin degrees of freedom. Using plaquette cluster dynamical mean-field theory, we find charge and spin criticality consistent with experimental results for organic conductors. In particular, the charge degree of freedom measured via the local density of states at the Fermi level shows a smoother transition than expected for the Ising universality class and in single-site dynamical mean-field theory, revealing the importance of short-ranged nonlocal correlations in two spatial dimensions. The spin criticality measured via the local spin susceptibility agrees quantitatively with nuclear magnetic resonance measurements of the spin-lattice relaxation rate.