Conducting state in a Mott insulator induced by a staggered field

Quenching has recently emerged as a transformative tool for dynamically evolving quantum systems into nonequilibrium phases with desirable properties. In the context of strongly correlated systems, such a tool can significantly alter their microscopic behavior and manifest a variety of interesting phenomena at the macroscopic level. We show that the staggered magnetic field can induce a nonequilibrium steady conducting state from the deep Mott insulating phase. The underlying mechanism can be abstracted from two-particle subspace, that is, the resonant staggered field combined with on-site interaction forced the particles to pair up and move like a free single particle. Correspondingly, the bound pair can have large energy bandwidth and exhibits the following dynamical behaviors. (i) When an electric field is applied, fast bound pair Bloch oscillation occurs, while a single electron is frozen. (ii) When a quenching resonant field is applied to an initial antiferromagnetic Mott insulating state, the final state becomes a doublon conducting state manifested by the nonzero eta correlator and large charge fluctuation. Our findings indicate that the cooperation of electron-electron correlation and modulated external field can provide an alternative pathway to access a new exotic quantum state that is absent in the ground-state phase diagram.