2018/07/31 by O. Ovdat, Omrie Ovdat, Yaroslav Don +2
Materials Science · Physics and Astronomy · #Charge (physics) #Chiral anomaly #Condensed matter physics #Coulomb #Dirac (video compression format) #Dirac fermion #Dirac sea #Electron #Graphene #Graphene research and applications #Physics #Quantum and electron transport phenomena #Quantum chromodynamics #Quantum electrodynamics #Quantum mechanics #Topological Materials and Phenomena #Vacancy defect #cond-mat.mes-hall #hep-th
paper · pdf · doi:10.1103/physrevb.102.075109
published as Phys. Rev. B 102, 075109 (2020) · 7 pages, 17 supplementary pages. 4 figures, 2 supplementary figures. V2
openalex publication_date 2020/08/07 · arxiv created 2020/08/10 · arxiv updated 2020/08/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The study of vacancies in graphene is a topic of growing interest. A single vacancy induces a localized stable charge of order unity interacting with other charges of the conductor through an unscreened Coulomb potential. It also breaks the symmetry between the two triangular graphene sublattices hence inducing zero energy states at the Dirac points. Here we show the fractional and pseudoscalar nature of this vacancy charge. A continuous Dirac model is presented which relates zero modes to vacuum fractional charge and to a parity anomaly. This relation constitutes an index theorem and is achieved by using particular chiral boundary conditions, which map the vacancy problem onto edge state physics. Vacancies in graphene thus allow us to realize prominent features of 2+1 quantum electrodynamics but without coupling to a gauge field. This essential difference makes vacancy physics relatively easy to implement and an interesting playground for topological state switching.