Photoinduced correlated electron dynamics in a two-leg ladder Hubbard system

TL;DR

This study investigates how photoirradiation affects electron dynamics in a two-leg ladder Hubbard model, revealing photoinduced metallic states and carrier coherence changes through numerical simulations.

Contribution

It demonstrates the photoinduced transition to metallic states and optical control of hole pairs in a ladder Hubbard system using exact diagonalization.

Findings

Photoinduced metallic-like state in half-filled Mott insulator

Suppression of low-energy carrier motion in hole-doped states

Optical control of hole pairs via double-pulse pumping

Abstract

Photoinduced carrier dynamics in a correlated electron system on a coupled two-leg ladder lattice are studied. The two-leg ladder Hubbard model is analyzed by utilizing the exact diagonalization method based on the Lanczos algorithm in finite size clusters. In order to reveal the transient carrier dynamics after photoirradiation, we calculate the low-energy components of the hole kinetic energy, the pair-field correlation function, the optical conductivity spectra and others. It is shown that the photoinduced metallic-like state appears in a half filled Mott insulating state, while the low-energy carrier motion is suppressed by photoirradiation in hole doped metallic states. These photoinduced changes in electron dynamics are associated with changes in the carrier-pair coherence, and are not attributed to a naive thermalization but to a ladder-lattice effect. Based on the numerical results, optical controls of hole pairs by using the double-pulse pumping are demonstrated. Implications to the recent optical pump-probe experiments are presented.