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

Graphene with vacancies: Supernumerary zero modes

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

Veröffentlichungsdatum dieses Volltextes: 25 Jun 2021 05:26
Artikel
DOI zum Zitieren dieses Dokuments: 10.5283/epub.46098


Zusammenfassung

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.



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Details

DokumentenartArtikel
Titel eines Journals oder einer ZeitschriftPhysical Review B
Verlag:American Physical Society (APS)
Band:94
Nummer des Zeitschriftenheftes oder des Kapitels:6
Seitenbereich:064204
Datum26 August 2016
InstitutionenPhysik > Institut für Theoretische Physik > Lehrstuhl Ferdinand Evers
Identifikationsnummer
WertTyp
10.1103/PhysRevB.94.064204DOI
Dewey-Dezimal-Klassifikation500 Naturwissenschaften und Mathematik > 530 Physik
StatusVeröffentlicht
BegutachtetJa, diese Version wurde begutachtet
An der Universität Regensburg entstandenZum Teil
URN der UB Regensburgurn:nbn:de:bvb:355-epub-460981
Dokumenten-ID46098

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