Real-time dynamics of particle-hole excitations in Mott insulator-metal junctions

TL;DR

This study investigates the real-time behavior of charge excitations in Mott insulators connected to metals, revealing how interactions influence charge transfer and spin correlations, with implications for energy harvesting in correlated materials.

Contribution

It provides the first detailed real-time analysis of holon-doublon dynamics in Mott insulator-metal junctions using time-dependent density matrix renormalization group methods.

Findings

Charge transfer is enhanced compared to noninteracting band insulators.

Holon-doublon propagation affects spin correlations and introduces phase shifts.

Charge dynamics depend on electron-electron interaction strength and voltage.

Abstract

Charge excitations in Mott insulators (MIs) are distinct from their band-insulator counterparts and they can provide a mechanism for energy harvesting in solar cells based on strongly correlated electronic materials. In this paper, we study the real-time dynamics of holon-doublon pairs in a MI connected to metallic leads using the time-dependent density matrix renormalization group method. The transfer of charge across the MI-metal interface is controlled by both the electron-electron interaction strength within the MI and the voltage difference between the leads. We find an overall enhancement of the charge transfer as compared to the case of a (noninteracting) band insulator-metal interface with a similar band gap. Moreover, the propagation of holon-doublon excitations within the MI dynamically changes the spin-spin correlations, introducing time-dependent phase shifts in the spin structure factor.