Recovery of the scattering symmetry looking at the conductance in asymmetric graphene nano-ribbons systems using pseudo-spin filters

López, Luis I A; Ujevic, Sebastian; Mendoza, Michel

doi:10.1088/1361-648x/ab015a

Cited by 3 publications

(4 citation statements)

References 39 publications

(54 reference statements)

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“…In figure 1(b) we show the effects generated by the potential barrier in the AGNR, system that behaves like a pseudospin filter [14,44,45]. The first effect observed is the generation of pseudospin polarizations and opposites on the sides of the barrier (for energies near the Dirac point), an effect that is only generated in the sublattice ES, see (i), this effect characterizes the pseudospin filter.…”

Section: Resultsmentioning

confidence: 97%

“…There is no report in the literature that this effect can be induced in monolayer graphene. Here in this work we show that one type of electronic cloaking can be induced in armchair graphene nanoribbons (AGNRs) [41][42][43] using potential barriers or pseudospin filters [14,44,45]. The pseudospin filters are potential barriers applied in AGNRs, these barriers induce opposite pseudospin polarizations on the sides of the barrier, also these system allow the contribution of hyperboloid subbands in the barrier region.…”

Section: Introductionmentioning

confidence: 93%

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Electronic cloaking effect of localized states induced in graphene nanoribbons

Mendoza

López

2021

J. Phys.: Condens. Matter

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The cloaking effect of electronic states was only reported in bilayer graphene. Here in this work we show that this effect can also be induced in armchair graphene nanoribbons (AGNRs), by potential barriers that modulate the chirality property of the system (correlation between pseudospins). These barriers manipulate the chirality and generates pseudospin polarizations on the sides of the barrier, which leaves spatial regions in evidence, in which states behave differently. In AGNRs the extended states (ES), associated with the tunneling of Klein, use only some sites in the nanoribbon lattice (sublattice of ES). On the other hand, the barrier applied in the nanoribbon, induces states totally localized within the region of the barrier, these states use only the sites not used by the sublattice of ES. The localized states remain invisible for electronic transport for all the energies and characteristics of the barrier in the region of the first effective transport band, the same as the states are changing. This electronic cloaking effect can be suppressed by the application of a magnetic field, detecting in the conductance the previously invisible states in the form of Fano resonances. We discuss here the possibility of using this cloaking effect to generate mechanisms that can hide information or to activate hidden system effects.

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 93%

Electronic cloaking effect of localized states induced in graphene nanoribbons

Mendoza

López

2021

J. Phys.: Condens. Matter

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“…On the other hand, Klein's tunneling in the nanoribbon can be modulated by potential barriers, through the loss of correlation between the chiral counterparts. The loss of correlation means that have contributions from the hyperboloid sub-bands, for energies close to the Dirac point, in the graphene nanoribbons with the increased potential of the barrier [32][33][34]. The conductance as a function of the increase in barrier potential (loss of correlation), as mentioned before, has a non-monotonic behavior [23,26].…”

Section: Introductionmentioning

confidence: 84%

“…These peaks are associated with quantum confinement between the barriers. On the other hand, in graphene systems confined by barriers, states are also confined within the potential barrier [32][33][34]. Thus, in general, in the conductance of these systems of graphene, we will find tunneling peaks associated with confinement inside and outside the barriers, which are mixed.…”

Section: Introductionmentioning

confidence: 95%

Effects analogous to the Kekulé distortion induced by pseudospin polarization in graphene nanoribbons: confinement and coupling by breakdown of chiral correlation

Mendoza¹,

Lopez²

2022

J. Phys.: Condens. Matter

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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.

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Chiral oscillations in electronic transport through graphene nanoribbons induced by pseudospin filters

López

Mendoza

2020

Phys. Rev. B

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Recovery of the scattering symmetry looking at the conductance in asymmetric graphene nano-ribbons systems using pseudo-spin filters

Cited by 3 publications

References 39 publications

Electronic cloaking effect of localized states induced in graphene nanoribbons

Electronic cloaking effect of localized states induced in graphene nanoribbons

Effects analogous to the Kekulé distortion induced by pseudospin polarization in graphene nanoribbons: confinement and coupling by breakdown of chiral correlation

Chiral oscillations in electronic transport through graphene nanoribbons induced by pseudospin filters

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