Surface alloy engineering in 2D trigonal lattice: giant Rashba spin splitting and two large topological gaps

Liu, Zhao; Jin, Yingdi; Yang, Yuchen; Wang, Z F; Yang, Jinlong

doi:10.1088/1367-2630/aaab98

Cited by 7 publications

(4 citation statements)

References 43 publications

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“…Further research by Bychkov and Rashba demonstrated that the Rashba effect also occurs in quasi-2D systems . Over the past few decades, the Rashba effect and Dresselhaus effect have been observed in various systems, such as 2D semiconductors, heterostructures, metal surfaces, 3D bulk materials, and quantum wells. ,,− …”

Section: Origin Of Rashba and Dresselhaus Effects In 2d Electron Gasmentioning

confidence: 99%

Spin–Orbit Coupling in 2D Semiconductors: A Theoretical Perspective

Chen

et al. 2021

J. Phys. Chem. Lett.

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This theoretical Perspective reviews spin−orbit coupling (SOC), including the Rashba effect and Dresselhaus effect, in two-dimensional (2D) semiconductors. We first introduce the origin of the Rashba effect and Dresselhaus effect using the Hamiltonian models; we then summarize 2D Rashba semiconductors predicted by first-principles density functional theory (DFT) calculations, including AB binary monolayers, Janus monolayers, 2D perovskites, and so on. We also review various manipulating techniques of the Rashba effect on 2D semiconductors, such as external electric field, strain engineering, charge doping, interlayer interactions, proximity effect of substrates, and external magnetic field. We then briefly summarize the applications of SOC, including the generation, detection, and manipulation of spin currents in spin Hall effect transistors and spin field effect transistors. Finally, we conclude this Perspective and propose three promising research fields of SOC in low-dimensional semiconductors, including the nonlinear SOC Hamiltonian model, 2D ferroelectric SOC semiconductors, and 1D Rashba model and semiconductors. This theoretical Perspective enriches the fundamental understanding of SOC in 2D semiconductors and will help in the design of new types of spintronic devices in future experiments.

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Section: Origin Of Rashba and Dresselhaus Effects In 2d Electron Gasmentioning

confidence: 99%

Spin–Orbit Coupling in 2D Semiconductors: A Theoretical Perspective

Chen

et al. 2021

J. Phys. Chem. Lett.

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“…However, due to the strict model requirement, 2D QTIs are only realized in these artificial systems, but seldom in electronic materials. This is dramatically different to the case of first-order 2D TIs, which are extensively studied in electronic materials. − To go beyond this limitation, hence, it is emergent to search more 2D QTIs in realistic electric materials.…”

mentioning

confidence: 97%

Two-Dimensional Quadrupole Topological Insulator in γ-Graphyne

et al. 2019

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Two-dimensional quadrupole topological insulator (2D QTI), as a new class of second-order topological phases, has been experimentally confirmed in various artificial systems recently. However, its realization in electronic materials has seldom been reported. In this work, we predict that the experimentally synthesized γ-graphyne is a large-gap (∼0.2 eV) 2D QTI. Three characterized features for 2D QTI are simultaneously observed in γ-graphyne: quantized finite bulk quadrupole moment, gapped topological edge states, and in-gap topological corner states. Intriguingly, we found that gapped topological edge states exist on armchair edge with CC (but not CC) termination, and in-gap topological corner states exist at corner with 120° (but not 60°) termination, which can be explained by different edge-hopping textures and corner chiral charges. Moreover, the robustness of in-gap topological corner states is further identified by varying edge-disorder and system-size calculations. Our results demonstrate a realistic electronic material for large-gap 2D QTI, which is expected to draw immediate experimental attention.

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“…S1 [51]). To identify the edge topology of TBG, based on recursive Green's function method [58,59], the semi-infinite spectral function along the edge cutting through AA-stacking region is calculated in both upper and lower gap, as shown in Figs. 3(a) and 3(b), respectively.…”

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confidence: 99%

Higher-Order Band Topology in Twisted Moiré Superlattice

Liu

Xian

et al. 2021

Phys. Rev. Lett.

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The two-dimensional (2D) twisted bilayer materials with van der Waals coupling have ignited great research interests, paving a new way to explore the emergent quantum phenomena by twist degree of freedom. Generally, with the decreasing of twist angle, the enhanced interlayer coupling will gradually flatten the low-energy bands and isolate them by two high-energy gaps at zero and full filling, respectively. Although the correlation and topological physics in the low-energy flat bands have been intensively studied, little information is available for these two emerging gaps. In this Letter, we predict a 2D secondorder topological insulator (SOTI) for twisted bilayer graphene and twisted bilayer boron nitride in both zero and full filling gaps. Employing a tight-binding Hamiltonian based on first-principles calculations, three unique fingerprints of 2D SOTI are identified, that is, nonzero bulk topological index, gapped topological edge state, and in-gap topological corner state. Most remarkably, the 2D SOTI exists in a wide range of commensurate twist angles, which is robust to microscopic structure disorder and twist center, greatly facilitating the possible experimental measurement. Our results not only extend the higher-order band topology to massless and massive twisted moiré superlattice, but also demonstrate the importance of high-energy bands for fully understanding the nontrivial electronics.

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Surface alloy engineering in 2D trigonal lattice: giant Rashba spin splitting and two large topological gaps

Cited by 7 publications

References 43 publications

Spin–Orbit Coupling in 2D Semiconductors: A Theoretical Perspective

Spin–Orbit Coupling in 2D Semiconductors: A Theoretical Perspective

Two-Dimensional Quadrupole Topological Insulator in γ-Graphyne

Higher-Order Band Topology in Twisted Moiré Superlattice

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