Title
Effects analogous to the Kekulé distortion induced by pseudospin polarization in graphene nanoribbons: Confinement and coupling by breakdown of chiral correlation
Date Issued
17 August 2022
Access level
metadata only access
Resource Type
journal article
Author(s)
Universidad Federal del Sur y Sudeste de Pará
Publisher(s)
Institute of Physics
Abstract
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 (width L and potential V) 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 of E, L and V for 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.
Volume
34
Issue
33
Language
English
OCDE Knowledge area
Física de la materia condensada
Scopus EID
2-s2.0-85132452821
PubMed ID
Source
Journal of Physics Condensed Matter
ISSN of the container
09538984
Source funding
Universidade Federal do ABC
Sponsor(s)
The authors acknowledge the financial support from ‘Universidade Federal do ABC’ and ‘Universidade Federal do Sul e Sudeste do Pará’.
Sources of information: Directorio de Producción Científica Scopus