Metal-insulator transition of the Kagome lattice fermions at 1/3 filling

TL;DR

This paper investigates the metal-insulator transition in a Kagome lattice of spinless fermions at 1/3 filling, revealing how the transition's nature varies with the sign of hopping integrals and analyzing the charge order and band structure effects.

Contribution

It provides a comparative analysis of the metal-insulator transition depending on hopping sign, using multiple computational methods and identifying distinct behaviors linked to band structure differences.

Findings

Charge-ordered ground state in strong coupling matches effective model predictions.

Transition properties differ qualitatively based on hopping sign.

Band structure at Fermi level influences transition nature.

Abstract

We discuss the metal-insulator transition of the spinless fermion model on the Kagom\'{e} lattice at 1/3-filling. The system is analyzed using exact diagonalization, the density-matrix renormalization group methods and the random phase approximation. In the strong-coupling region, the charge-ordered ground state is consistent with the predictions of the effective model with a plaquette order. We find that the qualitative properties of the metal-insulator transition are totally different depending on the sign of the hopping integrals, reflecting the difference of band structure at the Fermi level.