Kinetics of thermal Mott transitions in the Hubbard model

We present the first-ever multi-scale dynamical simulation of the temperature-controlled Mott metal-insulator transition in the Hubbard model. By integrating advanced electronic structure method and an efficient Gutzwiller/slave-boson solver into molecular dynamics simulations, we demonstrate that the transformation from a correlated metal to the Mott insulating phase proceeds via the nucleation and growth of the Mott droplets. Moreover, the time evolution of the Mott volume fraction is found to follow a universal transformation kinetics. We show that after an initial incubation period, the early stage of the phase transformation is characterized by a constant nucleation rate and an interface-controlled cluster growth mechanism, consistent with the classical theory developed by Kolmogorov, Johnson, Mehl, and Avrami. This is followed by a novel intermediate stage of accelerated phase transformation that is significantly different from the prediction of the classical theory. Moreover, the cluster-growth dynamics in this intermediate stage exhibits an unexpected avalanche behavior, similar to the Barkhausen noise in magnetization dynamics, even in the absence of quenched disorder. Detailed structural characterization further uncovers a universal correlation function for the transient mixed-phase states of the Mott transition. We also discuss implications of our findings for spatially resolved measurements of Mott metal-insulator transition obtained in recent nano-imaging experiments.

Gia-Wei Chern · 2019