Laser-induced ultrafast insulator-metal transition in $\text{BaBiO}_{3}$

TL;DR

This study demonstrates that strong laser pulses can induce an ultrafast insulator-to-metal transition in BaBiO3 within tens of femtoseconds, revealing complex dynamics involving high harmonics and gap reappearance.

Contribution

The paper provides a detailed theoretical analysis of laser-induced ultrafast phase transition in BaBiO3 using dynamical mean-field theory with realistic parameters.

Findings

Transition occurs within tens femtoseconds.

Charge density wave and energy gap vanish during transition.

Reappearance of the gap and high harmonic generation observed.

Abstract

We investigate ultra-fast coherent quantum dynamics of undoped $\text{BaBiO}_{3}$ driven by a strong laser pulse. Our calculations demonstrate that in a wide range of radiation frequencies and intensities the system undergoes a transient change from the insulating to the metallic state, where the charge density wave and the corresponding energy spectrum gap vanish. The transition takes place on the ultra-fast time scale of tens femtoseconds, comparable to the period of the corresponding lattice vibrations. The dynamics are determined by a complex interplay of the particle-hole excitation over the gap and of the tunnelling through it, giving rise to the highly non-trivial time evolution which comprises high harmonics and reveals periodic reappearance of the gap. The time evolution is obtained by solving the dynamical mean-field theory equations with the realistic parameters for the system and radiation. Results are summarized in the phase diagram, helpful for a possible experimental setup to achieve a dynamical control over the conduction state of this and other materials with the similarly strong electron-phonon interaction.