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Title: Dynamical fermion mass generation and exciton spectra in graphene

Abstract

The Coulomb interaction between massless Dirac fermions may induce dynamical chiral symmetry breaking by forming excitonic pairs in clean graphene, leading to semimetal-insulator transition. If the Dirac fermions have zero bare mass, an exact continuous chiral symmetry is dynamically broken and thus there are massless Goldstone excitons. If the Dirac fermions have a small bare mass, an approximate continuous chiral symmetry is dynamically broken and the resultant Goldstone-type excitons become massive, which is analogous to what happens in QCD. In this paper, after solving the Dyson-Schwinger gap equation in the presence of a small bare fermion mass, we found a remarkable reduction of the critical Coulomb interaction strength for excitonic pair formation and a strong enhancement of dynamical fermion mass. We then calculate the masses of Goldstone-type excitons using the Shifman-Vainshtein-Zakharov sum-rule method and operator product expansion technique developed in QCD and find that the exciton masses are much larger than bare fermion mass but smaller than the width of dynamical fermion mass gap. We also study the spin susceptibilities and estimate the masses of non-Goldstone-type excitons using the same tools.

Authors:
 [1];  [2];  [1]
  1. Department of Physics, National University of Defense Technology, Changsha, Hunan 410073 (China)
  2. Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)
Publication Date:
OSTI Identifier:
21538191
Resource Type:
Journal Article
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 83; Journal Issue: 11; Other Information: DOI: 10.1103/PhysRevB.83.115438; (c) 2011 American Institute of Physics; Journal ID: ISSN 1098-0121
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; APPROXIMATIONS; CARBON; CHIRAL SYMMETRY; EXCITONS; FERMIONS; HONEYCOMB STRUCTURES; INTERACTIONS; LAYERS; MASS; OPERATOR PRODUCT EXPANSION; QUANTUM CHROMODYNAMICS; REDUCTION; SEMIMETALS; SPECTRA; SPIN; SUM RULES; SYMMETRY BREAKING; ANGULAR MOMENTUM; CALCULATION METHODS; CHEMICAL REACTIONS; ELEMENTS; EQUATIONS; FIELD THEORIES; MECHANICAL STRUCTURES; NONMETALS; PARTICLE PROPERTIES; QUANTUM FIELD THEORY; QUASI PARTICLES; SERIES EXPANSION; SYMMETRY

Citation Formats

Chunxu, Zhang, Interdisciplinary Center for Theoretical Study, University of Science and Technology of China, Hefei, Anhui 230026, Guozhu, Liu, Institut fuer Theoretische Physik, Freie Universitaet Berlin, Arnimallee 14, D-14195 Berlin, and Mingqiu, Huang. Dynamical fermion mass generation and exciton spectra in graphene. United States: N. p., 2011. Web. doi:10.1103/PHYSREVB.83.115438.
Chunxu, Zhang, Interdisciplinary Center for Theoretical Study, University of Science and Technology of China, Hefei, Anhui 230026, Guozhu, Liu, Institut fuer Theoretische Physik, Freie Universitaet Berlin, Arnimallee 14, D-14195 Berlin, & Mingqiu, Huang. Dynamical fermion mass generation and exciton spectra in graphene. United States. https://doi.org/10.1103/PHYSREVB.83.115438
Chunxu, Zhang, Interdisciplinary Center for Theoretical Study, University of Science and Technology of China, Hefei, Anhui 230026, Guozhu, Liu, Institut fuer Theoretische Physik, Freie Universitaet Berlin, Arnimallee 14, D-14195 Berlin, and Mingqiu, Huang. Tue . "Dynamical fermion mass generation and exciton spectra in graphene". United States. https://doi.org/10.1103/PHYSREVB.83.115438.
@article{osti_21538191,
title = {Dynamical fermion mass generation and exciton spectra in graphene},
author = {Chunxu, Zhang and Interdisciplinary Center for Theoretical Study, University of Science and Technology of China, Hefei, Anhui 230026 and Guozhu, Liu and Institut fuer Theoretische Physik, Freie Universitaet Berlin, Arnimallee 14, D-14195 Berlin and Mingqiu, Huang},
abstractNote = {The Coulomb interaction between massless Dirac fermions may induce dynamical chiral symmetry breaking by forming excitonic pairs in clean graphene, leading to semimetal-insulator transition. If the Dirac fermions have zero bare mass, an exact continuous chiral symmetry is dynamically broken and thus there are massless Goldstone excitons. If the Dirac fermions have a small bare mass, an approximate continuous chiral symmetry is dynamically broken and the resultant Goldstone-type excitons become massive, which is analogous to what happens in QCD. In this paper, after solving the Dyson-Schwinger gap equation in the presence of a small bare fermion mass, we found a remarkable reduction of the critical Coulomb interaction strength for excitonic pair formation and a strong enhancement of dynamical fermion mass. We then calculate the masses of Goldstone-type excitons using the Shifman-Vainshtein-Zakharov sum-rule method and operator product expansion technique developed in QCD and find that the exciton masses are much larger than bare fermion mass but smaller than the width of dynamical fermion mass gap. We also study the spin susceptibilities and estimate the masses of non-Goldstone-type excitons using the same tools.},
doi = {10.1103/PHYSREVB.83.115438},
url = {https://www.osti.gov/biblio/21538191}, journal = {Physical Review. B, Condensed Matter and Materials Physics},
issn = {1098-0121},
number = 11,
volume = 83,
place = {United States},
year = {2011},
month = {3}
}