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 semimetalinsulator 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 Goldstonetype excitons become massive, which is analogous to what happens in QCD. In this paper, after solving the DysonSchwinger 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 Goldstonetype excitons using the ShifmanVainshteinZakharov sumrule 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 nonGoldstonetype excitons using the same tools.
 Authors:

 Department of Physics, National University of Defense Technology, Changsha, Hunan 410073 (China)
 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 10980121
 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, D14195 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, D14195 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, D14195 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, D14195 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 semimetalinsulator 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 Goldstonetype excitons become massive, which is analogous to what happens in QCD. In this paper, after solving the DysonSchwinger 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 Goldstonetype excitons using the ShifmanVainshteinZakharov sumrule 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 nonGoldstonetype 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 = {10980121},
number = 11,
volume = 83,
place = {United States},
year = {2011},
month = {3}
}