Extended dynamic Mott-transition in the two-band Hubbard model out of equilibrium

TL;DR

This paper investigates the non-equilibrium dynamical Mott transition in a two-band Hubbard model using a reformulated slave-boson mean-field approach, revealing a broad fluctuation regime and complex interorbital effects.

Contribution

It introduces a slave-boson mean-field reformulation of the time-dependent Gutzwiller approximation to study out-of-equilibrium Mott transitions in a two-band Hubbard model.

Findings

Interorbital fluctuations alter the transition dynamics.

A broad regime of long-lived metallic-insulating fluctuations emerges.

Mapping to a spin model elucidates the transition behavior.

Abstract

We reformulate the time-dependent Gutzwiller approximation by M. Schir\'o and M. Fabrizio [Phys. Rev. Lett. 105, 076401 (2010)] in the framework of slave-boson mean-field theory, which is used to investigate the dynamical Mott transition of the generic two-band Hubbard model at half filling upon an interaction quench. Interorbital fluctuations lead to notable changes with respect to the single-band case. The singular dynamical transition is replaced by a broad regime of long-lived fluctuations between metallic and insulating states, accompanied by intriguing precursor behavior. A mapping to a spin model proves helpful to analyze the different regions in terms of the evolution of an Ising-like order parameter. Contrary to the static case, singlet occupations remain vital in the Mott-insulating regime with finite Hund's exchange.