Edge States in Molecular Solid \alpha-(BEDT-TTF)2I3: Effects of Electron Correlations

TL;DR

This paper investigates how electron-electron interactions influence edge states in the molecular material -(BEDT-TTF)2I3, revealing conditions for gapless edge states and discovering a flux phase akin to topological Mott insulators.

Contribution

It introduces a detailed analysis of edge states in -(BEDT-TTF)2I3 considering electron correlations, highlighting the emergence of gapless states near phase boundaries and identifying a novel flux phase.

Findings

Charge-ordered phase has gapless edge states near phase boundary.

A flux phase caused by long-range Coulomb interaction is identified.

Edge states depend on the proximity to the phase transition.

Abstract

We examine the edge states of the Dirac electrons in the molecular material \alpha-(BEDT-TTF)2I3 with electron-electron interactions. Based on the analysis of the extended Hubbard model with the Hartree-Fock approximation, we show that the charge-ordered phase has the gapless edge states only in the vicinity of the phase boundary between the zero-gap state and the charge-ordered phase. We also show a peculiar flux phase caused by the long-range Coulomb interaction with the same mechanism as topological Mott insulator phase.