Two Independent Resonance Conditions in Asymmetrical Rectangular Triple-Barrier Structures

Zhao, Xinbao; Yamamoto, Hiroaki

doi:10.1002/(sici)1521-3951(199907)214:1<35::aid-pssb35>3.0.co;2-1

Cited by 7 publications

(5 citation statements)

References 7 publications

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“…In general, the use of these barriers in nanoribbons can confine the particles in the direction of electronic transport, generating tunneling peaks similar to those observed in the resonant tunneling of semiconductor heterostructures [35][36][37][38]. Tunneling peaks, in general, are observed in conductance, which can be related to T transmission through the Landauer-Büttiker formalism [35,38].…”

Section: Introductionmentioning

confidence: 85%

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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Section: Introductionmentioning

confidence: 85%

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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“…Systems like these are called resonant tunneling diodes [5,6,[50][51][52][53][54], and have been extensively studied experimentally. The modeling of the important properties of electronic transport in these systems is done in a dimension (1D), as for example, along the z axis [7,8].…”

Section: Discretization Of the Schrödinger Equation: Deduction Of The...mentioning

confidence: 99%

“…Several interesting and important effects were verified in these systems, as an example, we have the experimental verification of electronic transmission results, through multiple rectangular 1D barriers, which were theoretically anticipated using the Schrödinger equation. A well-studied effect in these systems is Resonant Tunneling [5][6][7][8], which shows transmission T = 1 through the discrete states generated in the quantum wells. These wells are induced by almost abrupt potential barriers, which are generated in the GaAs-AlGaAs semiconductor heterostructures.…”

Section: Introductionmentioning

confidence: 99%

Calculation method for the conductance of mesoscopic systems: assembly of Tight Binding Hamiltonians with spin effects—revisited

Silva

Mendoza

2023

J. Phys.: Condens. Matter

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We discretize the Schr"odinger equation in the approximation of the effective mass for the 2DEG of GaAs, without magnetic field and on the other hand, with magnetic field. This discretization leads naturally to Tight Binding Hamiltonians in the approximation of the effective mass. An analysis of this discretization allows us to gain insight into the role of site and hopping energies, which allows us to model the Tight Binding Hamiltonian assembly with spin: Zeeman and spin-orbit coupling effects, especially the case Rashba.With this tool we can assemble Hamiltonians of quantum boxes, Aharanov-Bohm interferometers, anti-dots lattices and effects of imperfections, as well as disorder in the system. The extension to mount quantum billiards is natural. We also explain here how to adapt the recursive equations of Green's functions for the case of spin modes, apart from transverse modes, for the calculation of conductance in these mesoscopic systems. The assembled Hamiltonians allow to identify the matrix elements (depending on the different parameters of the system) associated with splitting or spin flipping, which gives a starting point to model specific systems of interest, manipulating certain parameters. In general, the approach of this work allows us to clearly see the relationship between the wave and matrix description of quantum mechanics. We discuss here also, the extension of the method for 1D and 3D systems, for the extension apart from the first neighbors and for the inclusion of other types of interaction. The way we approach the method, has the objective of showing how specifically the site and hopping energies change in the presence of new interactions. This is very important in the case of spin interactions, because by looking at the matrix elements (site or hopping) we can directly identify the conditions that can lead to splitting, flipping or a mixture of these effects. Which is essential for the design of devices based on spintronics. Finally, we discuss spin-conductance modulation (Rashba spin precession) for the states of an open quantum dot (resonant states). Unlike the case of a quantum wire, the spin-flipping observed in the conductance is not perfectly sinusoidal, there is an envelope that modulates the sinusoidal component, which depends on the discrete-continuous coupling of the resonant states.

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“…In this respect, the electron transmission and resonant tunneling in one dimensional structures is a current problem in theoretical and experimental investigations [1][2][3][4]. Based on resonant tunneling phenomenon, experimental research on resonant tunneling diodes [5][6][7] and resonant tunneling transistors [8][9][10] have been carried out.…”

Section: Introductionmentioning

confidence: 96%

Electron transmission in symmetric and asymmetric double-barrier structures controlled by laser fields

Aktaş

Bilekkaya

Boz

et al. 2015

Superlattices and Microstructures

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Two Independent Resonance Conditions in Asymmetrical Rectangular Triple-Barrier Structures

Cited by 7 publications

References 7 publications

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

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

Calculation method for the conductance of mesoscopic systems: assembly of Tight Binding Hamiltonians with spin effects—revisited

Electron transmission in symmetric and asymmetric double-barrier structures controlled by laser fields

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