Mode mixing induced by disorder in a graphene 
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 junction in a magnetic field

Dai, Ning; Sun, Qing-Feng

doi:10.1103/physrevb.95.064205

Cited by 6 publications

(7 citation statements)

References 50 publications

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“…50,51 To calculate it in our device, the nonequilibrium Green's function method is used. [52][53][54] The local current between neighboring sites i and j is:…”

Section: Model and Methodsmentioning

confidence: 99%

Perfect valley filter based on a topological phase in a disordered Sb monolayer heterostructure

et al. 2018

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The hydrogenated Sb monolayer epitaxially grown on a LaFeO3 substrate is a novel type of two-dimensional material hosting quantum spin-quantum anomalous Hall (QS-QAH) states. For a device formed by Sb monolayer ribbon, the QAH edge states, belong to a single valley, are located at opposite edges of the ribbon. The QSH edge states, on the other hand, belong to the other valley and are distributed in a very narrow region at the same edge. In this paper, we find such material can be used to fabricate perfect valley filter. Adopting scattering matrix method and Green's function method, the valley resolved transport and spatial distribution of local current are calculated, in the present of Anderson disorder, edge defects and edge deformations. The numerical results demonstrate that, in the presence of above three types of disorder with moderate strength, the carriers can flow disspationless with nearly perfect valley polarization. Moreover, when the device becomes longer, the transport current does not decrease while the valley filter works even better. The origin is that the disorder can destroy the QSH edge states, but the valley-polarized QAH edge states can well hold.

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“…50,51 To calculate it in our device, the nonequilibrium Green's function method is used. [52][53][54] The local current between neighboring sites i and j is:…”

Section: Model and Methodsmentioning

confidence: 99%

Perfect valley filter based on a topological phase in a disordered Sb monolayer heterostructure

et al. 2018

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“…By applying the non-equilibrium Green's function method to the tightbinding Hamiltonian H in equation ( 1), the transmission coefficients T 1 and T 2 can be obtained quite straightforward by following the same procedure as in Refs. [41,42]. For small incident angle, the transmission coefficient T 1 is nearly a constant, and is insensitive to the incident energy E. As the incident angle increases, T 1 rapidly reduces and T 2 significantly increases.…”

Section: Double Refraction and Double Focusingmentioning

confidence: 99%

Double refraction and spin splitter in normal-conductor/hexagonal-semiconductor junctions

Dai

Sun

2018

Phys. Rev. B

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In analogy with light refraction at optical boundary, ballistic electrons also undergo refraction when propagate across a semiconductor junction. Establishing a negative refractive index in conventional optical materials is difficult, but the realization of negative refraction in electronic system is conceptually straightforward, which has been verified in graphene p-n junctions in recent experiments. Here, we propose a model to realize double refraction and double focusing of electric current by a normal-hexagonal semiconductor junction. The double refraction can be either positive or negative, depending on the junction being n-n type or p-n type. Based on the valley-dependent negative refraction, a spin splitter (valley splitter) is designed at the p-n junction system, where the spin-up and spin-down electrons are focused at different regions. These findings may be useful for the engineering of double lenses in electronic system and have underlying application of spin splitter in spintronics.

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“…( 1), the Green's function method is applied to solve the scattering amplitude S nm as well as conductance G in 3D TI PN junction. 40 The detailed procedure (formula) for solving S nm can refer Ref. [40].…”

Section: Conductance Of 3d Ti Pn Junctionmentioning

confidence: 99%

“…40 The detailed procedure (formula) for solving S nm can refer Ref. [40]. The Green's function method is flexible and available in different condition such as large filling factor, vertical bias, and disorder.…”

Section: Conductance Of 3d Ti Pn Junctionmentioning

confidence: 99%

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Quantum transport through three-dimensional topological insulator p-n junction under magnetic field

Dai

Zhou

et al. 2018

Phys. Rev. B

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The 3D topological insulator (TI) PN junction under magnetic fields presents a novel transport property which is investigated both theoretically and numerically in this paper. Transport in this device can be tuned by the axial magnetic field. Specifically, the scattering coefficients between incoming and outgoing modes oscillate with axial magnetic flux at the harmonic form. In the condition of horizontal mirror symmetry, the initial phase of the harmonic oscillation is dependent on the parities of incoming and outgoing modes. This symmetry is broken when a vertical bias is applied which leads to a kinetic phase shift added to the initial phase. On the other hand, the amplitude of oscillation is suppressed by the surface disorder while it has no influence on the phase of oscillation. Furthermore, with the help of the vertical bias, a special (1,-2) 3D TI PN junction can be achieved, leading to a novel spin precession phenomenon. arXiv:1808.07774v1 [cond-mat.mes-hall]

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Mode mixing induced by disorder in a graphene pnp junction in a magnetic field

Cited by 6 publications

References 50 publications

Perfect valley filter based on a topological phase in a disordered Sb monolayer heterostructure

Perfect valley filter based on a topological phase in a disordered Sb monolayer heterostructure

Double refraction and spin splitter in normal-conductor/hexagonal-semiconductor junctions

Quantum transport through three-dimensional topological insulator p-n junction under magnetic field

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