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Effects analogous to the Kekulé distortion induced by pseudospin polarization in graphene nanoribbons: confinement and coupling by breakdown of chiral correlation.
Mendoza, Michel; López, Luis I A.
Afiliação
  • Mendoza M; Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-170 Santo André, SP, Brazil.
  • López LIA; Instituto de Engenharia, Universidade Federal do Sul e Sudeste do Pará, Campus Santana do Araguaia, Rua Geraldo Ramalho 33, 68560-000 Santana do Araguaia, PA, Brazil.
J Phys Condens Matter ; 34(33)2022 Jun 17.
Article em En | MEDLINE | ID: mdl-35667369
We show here that potential barriers, applied to armchair nanoribbons, induce a hexagonal effective lattice, polarized in pseudospin on the sides of the barriers system, which has an effective unit cell greater than that of infinite graphene (pseudospin superstructure). This superstructure is better defined with the increase of the barrier potential, until a transport gap is generated. The superstructure, as well as the induced gap, are fingerprints of Kekulé distortion in graphene, so here we report an analogous effect in nanoribbons. These effects are associated with a breakdown of the chiral correlation. As a consequence, an effective zigzag edge is induced, which controls the electronic transport instead of the original armchair edge. With this, confinement effects (quasi-bound states) and couplings (splittings), both of chiral origin (decorrelation between chiral counterparts), are observed in the conductance as a function of the characteristics of the applied barriers and the number of barriers used. In general, the Dirac-like states in the nanoribbon can form quasi-bound states within potential barriers, which explains the Klein tunneling in armchair nanoribbons. On the other hand, for certain conditions of the barriers (widthLand potentialV) and the energy (E) of the quasi-particle, quasi-bound states between the barriers can be generated. These two types of confinement would be generating tunneling peaks, which are mixed in conductance. In this work we make a systematic study of conductance as a function ofE,LandVfor quantum dots systems in graphene nanoribbons, to determine fingerprints of chirality: line shapes and behaviors, associated with each of these two contributions. With these fingerprints of chirality we can detect tunneling through states within the barriers and differentiate these from tunneling through states formed between the barriers or quantum dot. With all this we propose a technique, from conductance, to determine the spatial region that the state occupies, associated with each tunneling peak.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Idioma: En Revista: J Phys Condens Matter Assunto da revista: BIOFISICA Ano de publicação: 2022 Tipo de documento: Article País de afiliação: Brasil País de publicação: Reino Unido

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Idioma: En Revista: J Phys Condens Matter Assunto da revista: BIOFISICA Ano de publicação: 2022 Tipo de documento: Article País de afiliação: Brasil País de publicação: Reino Unido