Evidence of electronic cloaking from chiral electron transport in bilayer graphene nanostructures

Lee, Kyung-Hoon; Lee, Seung–Hyun; Eo, Yun Suk; Kurdak, Çağlıyan; Zhong, Zhiyong

doi:10.1103/physrevb.94.205418

Cited by 15 publications

(16 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this case, it is necessary gapless bilayer graphene as well as low temperatures. The special dispersion relation of bilayer graphene 32 , 33 makes that electrons have at the same time a propagating and discrete character 34 , 35 . Actually, the degree of coupling between confined and continuum states is ruled by the transversal component of the wave vector.…”

Section: Introductionmentioning

confidence: 99%

Fano resonances in bilayer graphene superlattices

Briones-Torres

Rodrı́guez-Vargas

2017

Sci Rep

View full text Add to dashboard Cite

In this work, we address the ubiquitous phenomenon of Fano resonances in bilayer graphene. We consider that this phenomenon is as exotic as other phenomena in graphene because it can arise without an external extended states source or elaborate nano designs. However, there are not theoretical and/or experimental studies that report the impact of Fano resonances on the transport properties. Here, we carry out a systematic assessment of the contribution of the Fano resonances on the transport properties of bilayer graphene superlattices. Specifically, we find that by changing the number of periods, adjusting the barriers height as well as modifying the barriers and wells width it is possible to identify the contribution of Fano resonances on the conductance. Particularly, the coupling of Fano resonances with the intrinsic minibands of the superlattice gives rise to specific and identifiable changes in the conductance. Moreover, by reducing the angular range for the computation of the transport properties it is possible to obtain conductance curves with line-shapes quite similar to the Fano profile and the coupling profile between Fano resonance and miniband states. In fact, these conductance features could serve as unequivocal characteristic of the existence of Fano resonances in bilayer graphene.

show abstract

Section: Introductionmentioning

confidence: 99%

Fano resonances in bilayer graphene superlattices

Briones-Torres

Rodrı́guez-Vargas

2017

Sci Rep

View full text Add to dashboard Cite

show abstract

“…The pseudospin is a characteristic of two-level quantum systems such as honeycomb lattices [26]. The pseudospin is involved in most of the exotic properties of 2D materials, including the electronic cloaking in bilayer graphene [5,9].…”

Section: (B)(d)mentioning

confidence: 99%

Electronic cloaking of confined states in phosphorene junctions

Molina-Valdovinos,

Lamas-Martínez,

Briones-Torres

et al. 2021

Preprint

View full text Add to dashboard Cite

We study the electronic transport of armchair and zigzag gated phosphorene junctions. We find confined states for both direction-dependent phosphorene junctions.In the case of armchair junctions confined states are reflected in the transmission properties as Fabry-Pérot resonances at normal and oblique incidence. In the case of zigzag junctions confined states are invisible at normal incidence, resulting in a null transmission. At oblique incidence Fabry-Pérot resonances are presented in the transmission as in the case of armchair junctions. This invisibility or electronic cloaking is related to the highly direction-dependent pseudospin texture of the charge carriers in phosphorene. Electronic cloaking is also manifested as a series of singular peaks in the conductance and as inverted peaks in the Seebeck coefficient. The characteristics of electronic cloaking are also susceptible to the modulation of the phosphorene bandgap and an external magnetic field. So, electronic cloaking in phosphorene junctions in principle could be tested through transport, thermoelectric or magnetotransport measurements.Cloaking effect consists in making objects invisible to radiation, acoustic waves, matter waves, heat and charge fluxes, among others [1][2][3][4]. The typical cloaking effect is based on guiding plane waves around an object. The effect also refers to hiding an object in space.Cloaking effect is a phenomenon that can have a plethora of applications such as mantle cloaking, antennas, invisible sensors that do not perturb the field that they measure, etc. [1].With the arrival of 2D materials, in particular graphene, there were reports of the cloaking effect in bilayer graphene junctions [5][6][7] and graphene nanoribbons [8]. Experimental evi- *

show abstract

“…Regarding bilayer graphene 31 , it harbors exotic effects that could substantially improve the Seebeck coefficient and the power factor, and consequently giving rise to high values of ZT . Among these effects we can find anti-Klein tunneling 32 , 33 , cloaked states 33 , 34 , and Fano and hybrid resonances 35 – 39 . In the case of Fano resonances, it is known that they are related to the chiral nature of electrons in bilayer graphene 33 , 34 , 38 .…”

Section: Introductionmentioning

confidence: 95%

“…Among these effects we can find anti-Klein tunneling 32 , 33 , cloaked states 33 , 34 , and Fano and hybrid resonances 35 – 39 . In the case of Fano resonances, it is known that they are related to the chiral nature of electrons in bilayer graphene 33 , 34 , 38 . In particular, they arise due to the chiral matching between electron states inside and outside electrostatic barriers at oblique incidence 35 – 38 , 40 .…”

Section: Introductionmentioning

confidence: 95%

Enhancement of the thermoelectric properties in bilayer graphene structures induced by Fano resonances

Briones-Torres

Pérez‐Álvarez

Molina-Valdovinos

et al. 2021

Sci Rep

View full text Add to dashboard Cite

Fano resonances of bilayer graphene could be attractive for thermoelectric devices. The special profile presented by such resonances could significantly enhance the thermoelectric properties. In this work, we study the thermoelectric properties of bilayer graphene single and double barrier structures. The barrier structures are typically supported by a substrate and encapsulated by protecting layers, reducing considerably the phonon thermal transport. So, we will focus on the electronic contribution to the thermal transport. The charge carriers are described as massive chiral particles through an effective Dirac-like Hamiltonian. The Hybrid matrix method and the Landauer–Büttiker formalism are implemented to obtain the transmission, transport and thermoelectric properties. The temperature dependence of the Seebeck coefficient, the power factor, the figure of merit and the efficiency is analyzed for gapless single and double barriers. We find that the charge neutrality point and the system resonances shape the thermoelectric response. In the case of single barriers, the low-temperature thermoelectric response is dominated by the charge neutrality point, while the high-temperature response is determined by the Fano resonances. In the case of double barriers, Breit–Wigner resonances dominate the thermoelectric properties at low temperatures, while Fano and hybrid resonances become preponderant as the temperature rises. The values for the figure of merit are close to two for single barriers and above three for double barriers. The system resonances also allows us to optimize the output power and the efficiency at low and high temperatures. By computing the density of states, we also corroborate that the improvement of the thermoelectric properties is related to the accumulation of electron states. Our findings indicate that bilayer graphene barrier structures can be used to improve the response of thermoelectric devices.

show abstract

Evidence of electronic cloaking from chiral electron transport in bilayer graphene nanostructures

Cited by 15 publications

References 43 publications

Fano resonances in bilayer graphene superlattices

Fano resonances in bilayer graphene superlattices

Electronic cloaking of confined states in phosphorene junctions

Enhancement of the thermoelectric properties in bilayer graphene structures induced by Fano resonances

Contact Info

Product

Resources

About