Algebraic structure of Dirac fermion state in \alpha-(BDET-TTF)_2I_3

TL;DR

This paper investigates the algebraic structure of Dirac fermions in the organic conductor -(BDET-TTF)_2I_3, revealing generators related to chirality and deriving an analytic expression for Dirac point positions.

Contribution

It introduces a pair of generators for the Hamiltonian that describe Dirac fermion chirality and relates phase parameters to Dirac point positions, providing a reduced Hamiltonian with analytic Dirac point expressions.

Findings

Identified generators for the Hamiltonian related to Dirac fermion chirality

Established relationship between phase parameters and Dirac point positions

Derived an analytic formula for Dirac point locations in the Brillouin zone

Abstract

We study the algebraic structure of the Dirac fermion state in the organic conductor, \alpha-(BDET-TTF)_2I_3. We find a pair of generators for the Hamiltonian of \alpha-(BDET-TTF)_2I_3 that describes the chirality of Dirac fermions. The phase parameters associated with those generators have an intimate and simple relationship with the positions of the Dirac points in the Brillouin zone. By making use of the form of the generators, a reduced form of the Hamiltonian is constructed that shares some characteristic features of the Dirac fermions with \alpha-(BDET-TTF)_2I_3. For the reduced Hamiltonian we present the analytic expression for the Dirac point position that sits at arbitrary point in the Brillouin zone determined by the hopping parameters.