Charge dynamics in doped Mott insulators on a honeycomb lattice

TL;DR

This study explores charge transport in doped Mott insulators on a honeycomb lattice, revealing how pseudogap effects influence conductivity spectra and lead to universal features across different lattice types.

Contribution

It introduces a theoretical analysis of pseudogap effects on charge dynamics in doped honeycomb-lattice Mott insulators, highlighting universal conductivity features.

Findings

Pseudogap causes a low-energy non-Drude peak and midinfrared band in conductivity.

Increasing doping reduces the pseudogap, shifting the midinfrared band towards low energy.

Universal two-component conductivity is observed in both honeycomb and square-lattice Mott insulators.

Abstract

Within the framework of the fermion-spin theory, the charge transport in the doped Mott insulators on a honeycomb lattice is studied by taking into account the pseudogap effect. It is shown that the conductivity spectrum in the low-doped regime is separated by the pseudogap into a low-energy non-Drude peak followed by a broad midinfrared band. However, the decrease of the pseudogap with the increase of doping leads to a shift of the position of the midinfrared band towards to the low-energy non-Drude peak, and then the low-energy Drude behavior recovers in the high-doped regime. The combined results of both the doped honeycomb-lattice and square-lattice Mott insulators indicate that the two-component conductivity induced by the pseudogap is a universal feature in the doped Mott insulators.