Prediction of large-gap quantum spin hall insulator and Rashba-Dresselhaus effect in two-dimensional g-TlA (A = N, P, As, and Sb) monolayer films

Li, Xinru; Dai, Ying; Ma, Yandong; Wei, Wei; Lin, Yanfen; Huang, Baibiao

doi:10.1007/s12274-015-0800-4

Cited by 51 publications

(43 citation statements)

References 40 publications

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“…Although many materials are theoretically predicted to be 2D TIs, [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] the experimentally observed QSH effect is limited in HgTe/CdTe and InAs/GaSb quantum wells. Although many materials are theoretically predicted to be 2D TIs, [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] the experimentally observed QSH effect is limited in HgTe/CdTe and InAs/GaSb quantum wells.…”

Section: Introductionmentioning

confidence: 99%

Quantum spin hall insulators in strain-modified arsenene

2015

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By means of density functional theory (DFT) computations, we predict that the suitable strain modulation of honeycomb arsenene results in a unique two-dimensional (2D) topological insulator (TI) with a sizable bulk gap (up to 696 meV), which could be characterized and utilized at room temperature. Without considering any spin-orbit coupling, the band inversion occurs around the Gamma (G) point at tensile strains larger than 11.7%, which indicates the quantum spin Hall effect in arsenene at appropriate strains. The nontrivial topological phase was further confirmed by the topological invariant ν = 1 and edge states with a single Dirac-type crossing at the G point. Our results provide a promising strategy for designing 2D TIs with large bulk gaps from commonly used materials.

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Section: Introductionmentioning

confidence: 99%

Quantum spin hall insulators in strain-modified arsenene

2015

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“…46,47 Because of the surface nature, the contributions of the Ag SSs on the transport properties are lower than those from the bulk-nature Ag QWSs. The spin-band splitting can commonly be described by the Bychkov-Rashba model 48,49 and the Rashba parameter can be estimated by α R = ΔE/(2k x ). 36 As indicated by the green vertical arrow in Figure 2e, the α R obtained in our Ag QWS splitting reaches 1.75 eV A, which is one order of magnitude larger than that of the Ag SS splitting.…”

Section: Resultsmentioning

confidence: 99%

Newtype large Rashba splitting in quantum well states induced by spin chirality in metal/topological insulator heterostructures

Chang

Jeng

2016

NPG Asia Mater

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In a two-dimensional system without inversion symmetry, such as a surface or interface, the potential-asymmetry-induced electric field can create the Rashba effect, which is spin-band splitting caused by spin-orbit coupling (SOC). On the basis of Rashba splitting, several promising spintronic devices, such as the Datta-Das spin transistor, have been designed for manipulating spin precession in the absence of a magnetic field. Rashba splitting can be created in several metal quantum well states (QWSs), such as in Pb/Si; however, the effect is usually moderate because the itinerant carriers within the metal film strongly screen out the electric field. A large Rashba splitting can be found in the unoccupied QWSs of the Bi monolayer on Cu (111); however, the metallic substrate limits the diversity of its applications. To achieve strong Rashba splitting in metal thin film based on an insulating substrate, which is most desirable, we propose the normal metal (NM)/topological insulator (TI) heterostructure for manufacturing Rashba-type splitting in NM QWSs. In such a hybrid system, the TI spin-momentum-locking Dirac surface state associated with SOC strongly modifies the penetration depth of the NM QWS into the TI substrate according to the spin orientation, leading to strong Rashba-type splittings in the NM QWS. Combining ab initio calculations and analytical modeling, the momentum separation of the Rashba splitting in the NM QWS can be as large as 0.18 Å − 1 , which is the largest ever found in metal-film/non-metallic substrate systems. Furthermore, the induced spin polarization in the Rashba band is nearly 100%, much higher than the typical value of 40-50% in the TI surface state itself. This remarkably large Rashba splitting and the high spin polarization in the NM QWS evoked by the spin chirality of the TI surface state confer great potential for the development of spintronic devices. INTRODUCTIONOne of the major tasks in the development of semiconductor spintronics is finding a material with remarkable Rashba-type splitting to control the spin current. For example, the Datta-Das spin transistor, 1 proposed for more than 20 years, switches the spin current by controlling the magnitude of Rashba splitting of a two-dimensional electron gas in a semiconductor heterostructure. [2][3][4][5][6] After decades of trials, the Datta-Das spin transistor has finally been experimentally realized recently. 7 However, the mild splitting of the two-dimensional electron gas bands is inapplicable for spin transistors working at room temperature or designed in the nanoscale. 7-9 A much more feasible approach is thus highly desirable.Alternatively, giant Rashba splittings can be found in the surface state (SS) of noble-metal-based surface alloys with strong spin-orbit couplings (SOCs) in heavy atoms. 10,11 The interatomic electric field at the surface-alloy plane is the key to the giant splitting. 12 Regarding the influence of the metal host, the SS would be hidden in the spintronics functions; therefore, efforts have been made on s...

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“…structure TlM counterpart 34 . The perpendicular bonding between the two monolayers results in the bilayer TlM (M = N, P, As, Sb) systems, the crystal structure is shown in Fig.1 (a).…”

Section: Resulats and Discussionmentioning

confidence: 99%

Large gap two dimensional topological insulators: the bilayer triangular lattice TlM (M = N, P, As, Sb)

2017

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Based on density functional theory and Berry curvature calculations, we predict that p-p band inversion type quantum spin Hall effect (QSHE) can be realized in a series of two dimensional (2D) bilayer honeycomb TlM (M = N, P, As, Sb), which can be effectively equivalent to bilayer triangular lattice for low energy electrons. Further topological analysis reveals that the band inversion between p − z and px,y of M atom contributes to the nontrivial topological nature of TlM. The band inversion is independent of spin-orbit coupling which is distinctive from conventional topological insulators (TIs). A tight binding model based on triangle lattice is constructed to describe the QSH states in the systems. Besides the interesting 2D triangular lattice p − p type inversion for the topological mechanism, the maximal local band gap of the systems can reach 550 meV (TlSb), which provides a new choice for future room temperature quantum spin Hall Insulator (QSHI). Considering the advance of the technology of van der Waals passivation, combining with hexagonal materials, such as h-BN, TlMs show great potential for future 2D topological electronic devices.

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Prediction of large-gap quantum spin hall insulator and Rashba-Dresselhaus effect in two-dimensional g-TlA (A = N, P, As, and Sb) monolayer films

Cited by 51 publications

References 40 publications

Quantum spin hall insulators in strain-modified arsenene

Quantum spin hall insulators in strain-modified arsenene

Newtype large Rashba splitting in quantum well states induced by spin chirality in metal/topological insulator heterostructures

Large gap two dimensional topological insulators: the bilayer triangular lattice TlM (M = N, P, As, Sb)

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