Wednesday, March 13, 2013

1303.2886 (Masaki Hirotsu et al.)

Position space formulation for Dirac fermions on honeycomb lattice    [PDF]

Masaki Hirotsu, Tetsuya Onogi, Eigo Shintani
We study how to construct Dirac fermion defined on the honeycomb lattice in position space. Starting from the nearest neighbor interaction in tight binding model, we show that the Hamiltonian is constructed by kinetic term and second derivative term of three flavor Dirac fermions in which one flavor has a mass of cutoff order and the other flavors are massless. In this formulation the structure of the Dirac point is simplified so that its uniqueness can be easily shown even if we consider the next-nearest neighbor interaction. We also explicitly show that there exists an exact chiral symmetry at finite lattice spacing, which protects the masslessness of the Dirac fermion, and discuss the analogy with the staggered fermion formulation.
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