Topological junctions in high-Chern-number quantum anomalous Hall systems

Han, Yulei; Pan, Shiyao; Qiao, Zhenhua

doi:10.1103/physrevb.108.115302

Cited by 4 publications

(3 citation statements)

References 54 publications

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“…It has been found that graphene-like materials can exhibit abundant topological phases under different external fields applied to the whole system, [11][12][13][14][15] and the side potential applied to the boundary of the system is also crucial for generating and manipulating topological phases and corresponding edge states. [16,17] In particular, a large number of zero-line modes (ZLMs) [18][19][20] that can arise from the interface separating different topological phases have been found in addition to outer edge states [11,[21][22][23] induced at the interface between topological phases and the topologically trivial vacuum. In particular, ZLMs are related not only to the Chern numbers but also to the valley Chern numbers, which are also known as kink states and inner edge states, respectively.…”

Section: Introductionmentioning

confidence: 99%

Fully spin-polarized, valley-polarized and spin-valley-polarized electron beam splitters utilizing zero-line modes in a three-terminal device

Lü 吕,

Yang 杨,

Xie 谢

2024

Chinese Phys. B

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Topological zero-line modes (ZLMs) with spin and valley degrees of freedom gives rise to the spin, valley and spin-valley transports, which support a platform to explore the quantum transport physics and potential applications in the spintonic/valleytronic devices. In this work, we investigate the beam-splitting behaviors of the charge current devoted by the ZLMs in a three-terminal system. It shows that with special combinations of the ZLMs, the incident charge current along the interface between different topological phases can be divided into different polarized currents with unit transmittance in two outgoing terminals. As a result, the fully spin-polarized, valley-polarized and spin-valley-polarized electron beam splitters are generated. And the mechanism of these splitters is attributed to the cooperative effects of the distribution of the ZLMs, and the intervalley and intravalley scatterings that are modulated by the wave-vector mismatch and group velocity mismatch. Interestingly, a half-quantized transmittance of these scatterings is found in a fully spin-valley-polarized electron beam splitter. Furthermore, the results indicate that these splitters can be applicable to graphene, silicene, germanene and stanene due to the robustness against the spin-orbit coupling. Our findings offer a new view to understand the transport mechanism and investigate the promising applications of the ZLMs.

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Section: Introductionmentioning

confidence: 99%

Fully spin-polarized, valley-polarized and spin-valley-polarized electron beam splitters utilizing zero-line modes in a three-terminal device

Lü 吕,

Yang 杨,

Xie 谢

2024

Chinese Phys. B

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“…Quasi-1D chiral edge and interface states and their quantum transport properties in QAHE set-ups in the presence of DWs have been studied theoretically in a few papers using effective continuum models for the magnetic TI surfaces [30][31][32]. The nature of the states at the DW can be controlled by an external electric field.…”

Section: Introductionmentioning

confidence: 99%

“…It can be shown that the equilibrium charge current along the DW in a 3D TI in the presence of a local Zeeman field, is equal to the sum of counter-propagating equilibrium currents flowing along the external boundaries of the domains [31]. The number of chiral interface modes along the DW is determined by the difference of Chern numbers of adjacent regions, the tuning of which can be used to manipulate the current partition at the DW junctions [32]. Note that earlier theoretical work had predicted that robust edge and interface states should occur in graphene heterostructure QHE bars along the edges and the DWs created at the interface of two adjacent regions under the effect of oppositely oriented magnetic fields.…”

Section: Introductionmentioning

confidence: 99%

Chiral edge transport along domain walls in magnetic topological insulator nanoribbons

Pournaghavi,

Canali

2024

J. Phys.: Condens. Matter

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Quantum anomalous Hall insulators are topologically characterized by non-zero integer Chern numbers, the sign of which depends on the direction of the exchange field that breaks time-reversal symmetry. This feature allows the manipulation of the conducting chiral edge states present at the interface of two magnetic domains with opposite magnetization and opposite Chern numbers.Motivated by this broad understanding, the present study investigates the quantum transport properties of a magnetized $Bi_2Se_3$ topological insulator nanoribbon with a domain wall oriented either parallel or perpendicular to the transport direction. Employing an atomistic tight-binding model and a non-equilibrium Green's function formalism, we calculate the quantum conductance and explore the nature of the edge states. We elucidate the conditions leading to exact conductance quantization and identify the origin of deviations from this behavior.Our analysis shows that although the conductance is quantized in the presence of the horizontal domain wall, the quantization is absent in the perpendicular domain wall case. Furthermore, the investigation of the spin character of the edge modes confirms that the conductance in the horizontal domain wall configuration is spin polarized. This finding underscores the potential of our system as a simple three dimensional spin-filter device.

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Robust topological bound states in the continuum in a quantum Hall bar with an anti-dot

Díaz-Bonifaz,

Ramírez

2024

Physica E: Low-dimensional Systems and Nanostructures

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Topological junctions in high-Chern-number quantum anomalous Hall systems

Cited by 4 publications

References 54 publications

Fully spin-polarized, valley-polarized and spin-valley-polarized electron beam splitters utilizing zero-line modes in a three-terminal device

Fully spin-polarized, valley-polarized and spin-valley-polarized electron beam splitters utilizing zero-line modes in a three-terminal device

Chiral edge transport along domain walls in magnetic topological insulator nanoribbons

Robust topological bound states in the continuum in a quantum Hall bar with an anti-dot

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