Effects of flavor-symmetry violation from staggered fermion lattice simulations of graphene

Journal Article · Sat Jan 15 00:00:00 EST 2011 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.83.045420· OSTI ID:21538070

Giedt, Joel; Nayak, Saroj ^[1]; Skinner, Andrew ^[2]

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1. Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180-3590 (United States)
2. Physics Department, Skidmore College, 815 North Broadway, Saratoga Springs, New York 12866 (United States)

We analyze the effects of flavor splitting from staggered fermion lattice simulations of a low-energy effective theory for graphene. Both the unimproved action and the tadpole-improved action with a Naik term show significant flavor-symmetry breaking in the spectrum of the Dirac operator. Note that this is true even in the vicinity of the second-order phase transition point where it has been argued that the flavor-symmetry breaking should be small due to the continuum limit being approached. We show that at weaker couplings the flavor splitting is drastically reduced by stout link smearing, while this mechanism is ineffective at the stronger couplings relevant to suspended graphene. We also measure the average plaquette and describe how it calls for a reinterpretation of previous lattice Monte Carlo simulation results, due to tadpole improvement. After taking into account these effects, we conclude that previous lattice simulations are possibly indicative of an insulating phase, although the effective number of light flavors could be effectively less than two due to the flavor-splitting effects. If that is true, then simulations with truly chiral fermions (such as overlap fermions) are needed in order to settle the question.

• OSTI ID: 21538070
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 83, Issue 4; Other Information: DOI: 10.1103/PhysRevB.83.045420; (c) 2011 American Institute of Physics; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CARBON
CHIRALITY
COMPUTERIZED SIMULATION
COUPLING
DIRAC OPERATORS
FERMIONS
HONEYCOMB STRUCTURES
LATTICE FIELD THEORY
MONTE CARLO METHOD
PHASE TRANSFORMATIONS
SPECTRA
SYMMETRY BREAKING
CALCULATION METHODS
CONSTRUCTIVE FIELD THEORY
ELEMENTS
FIELD THEORIES
MATHEMATICAL OPERATORS
MECHANICAL STRUCTURES
NONMETALS
PARTICLE PROPERTIES
QUANTUM FIELD THEORY
QUANTUM OPERATORS
SIMULATION