Direkt zum Inhalt

Weik, Norman ; Schindler, Johannes ; Bera, Soumya ; Solomon, Gemma C. ; Evers, Ferdinand

Graphene with vacancies: Supernumerary zero modes

Article

Weik, Norman, Schindler, Johannes, Bera, Soumya, Solomon, Gemma C. and Evers, Ferdinand (2016) Graphene with vacancies: Supernumerary zero modes. Physical Review B 94 (6), 064204.

DOI to cite this document: 10.5283/epub.46098


Abstract

The density of states ϱ(E) of graphene is investigated within the tight-binding (Hückel) approximation in the presence of vacancies. They introduce a nonvanishing density of zero modes nzm that act as midgap states, ϱ(E)=nzmδ(E)+smooth. As is well known, the actual number of zero modes per sample can, in principle, exceed the sublattice imbalance, Nzm≥∣∣NA−NB∣∣, where NA,NB denote the number of ...

The density of states ϱ(E) of graphene is investigated within the tight-binding (Hückel) approximation in the presence of vacancies. They introduce a nonvanishing density of zero modes nzm that act as midgap states, ϱ(E)=nzmδ(E)+smooth. As is well known, the actual number of zero modes per sample can, in principle, exceed the sublattice imbalance, Nzm≥∣∣NA−NB∣∣, where NA,NB denote the number of carbon atoms in each sublattice. In this paper, we establish a stronger relation that is valid in the thermodynamic limit and that involves the concentration of zero modes, nzm>∣∣cA−cB∣∣, where cA and cB denote the concentration of vacancies per sublattice; in particular, nzm is nonvanishing even in the case of balanced disorder, NA/NB=1. Adopting terminology from benzoid graph theory, the excess modes associated with the current carrying backbone (percolation cluster) are called supernumerary. In the simplest cases, such modes can be associated with structural elements such as carbon atoms connected with a single bond, only. Our result suggests that the continuum limit of bipartite hopping models supports nontrivial “supernumerary” terms that escape the present continuum descriptions.



Involved Institutions


Details

Item typeArticle
Journal or Publication TitlePhysical Review B
PublisherAmerican Physical Society (APS)
Open Access TypeDue to SHERPA/RoMEO
Volume94
Number of Issue or Book Chapter6
Page Range064204
Date26 August 2016
Date of publication25 Jun 2021 05:26
InstitutionsPhysics > Institute of Theroretical Physics > Chair Ferdinand Evers
Identification Number
ValueType
10.1103/PhysRevB.94.064204DOI
Dewey Decimal Classification500 Science > 530 Physics
StatusPublished
RefereedYes, this version has been refereed
Created at the University of RegensburgPartially
URN of the UB Regensburgurn:nbn:de:bvb:355-epub-460981
Item ID46098

Export bibliographical data

Owner only: item control page

nach oben