Incommensurate Mott Insulator in One-Dimensional Electron Systems close to Quarter Filling

TL;DR

This paper investigates how incommensurate potentials in one-dimensional electron systems near quarter filling can induce a Mott insulator phase, explaining observed metal-insulator transitions in certain molecular conductors.

Contribution

It introduces the concept of an incommensurate Mott insulator driven by incommensurate potentials, expanding understanding of metal-insulator transitions in low-dimensional systems.

Findings

Incommensurate Mott insulator can be realized in 1D systems with incommensurate potentials.

The interplay between commensurability energy and incommensurate potential is crucial.

The theory explains the metal-insulator transition observed in (MDT-TS)(AuI₂)₀.441.

Abstract

A possibility of a metal-insulator transition in molecular conductors has been studied for systems composed of donor molecules and fully ionized anions with an incommensurate ratio close to 2:1 based on a one-dimensional extended Hubbard model, where the donor carriers are slightly deviated from quarter filling and under an incommensurate periodic potential from the anions. By use of the renormalization group method, interplay between commensurability energy on the donor lattice and that from the anion potential has been studied and it has been found that an "incommensurate Mott insulator" can be generated. This theoretical finding will explain the metal-insulator transition observed in (MDT-TS)(AuI$_2$)$_{0.441}$.