Induced ferromagnetism in one-side semihydrogenated silicene and germanene

Wang, Xinquan; Li, Handong; Wang, Jiantao

doi:10.1039/c2cp23385a

Cited by 172 publications

(146 citation statements)

References 46 publications

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“…Due to strong spin-orbit coupling (SOC), the quantum spin Hall effect may be observed in silicene in an experimentally accessible temperature regime [13]. A tunable band gap can be opened up to about 4 eV in silicene by applying a perpendicular electric field [21][22] and by hydrogenation [23][24][25][26], halogenation [27][28], and oxidation [29][30]. Owing to these excellent properties and easy integration into the current Si-based semiconductor technology, silicene holds great promise for future applications in nanoelectronic devices.…”

Section: Introductionmentioning

confidence: 99%

Point defects in epitaxial silicene on Ag(111) surfaces

Liu

Feng

et al. 2016

2D Mater.

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Silicene, a counterpart of graphene, has achieved rapid development due to its exotic electronic properties and excellent compatibility with the mature silicon-based semiconductor technology. Its low room-temperature mobility of ~100 cm2 V−1 s−1, however, inhibits device applications such as in field-effect transistors. Generally, defects and grain boundaries would act as scattering centers and thus reduce the carrier mobility. In this paper, the morphologies of various point defects in epitaxial silicene on Ag(111) surfaces have been systematically investigated using first-principles calculations combined with experimental scanning tunneling microscope (STM) observations. The STM signatures for various defects in epitaxial silicene on Ag(111) surface are identified. In particular, the formation energies of point defects in Ag(111)-supported silicene sheets show an interesting dependence on the superstructures, which, in turn, may have implications for controlling the defect density during the synthesis of silicene. Through estimating the concentrations of various point defects in different silicene superstructures, the mystery of the defective appearance of $\sqrt{13}\times \sqrt{13}$ and $2\sqrt{3}\times 2\sqrt{3}$ silicene in experiments is revealed, and 4 x 4 silicene sheet is thought to be the most suitable structure for future device applications. , however, inhibits device applications such as in field-effect transistors. Generally, defects and grain boundaries would act as scattering centers and thus reduce the carrier mobility. In this paper, the morphologies of various point defects in epitaxial silicene on Ag(111) surfaces have been systematically investigated using first-principles calculations combined with experimental scanning tunneling microscope (STM) observations. The STM signatures for various defects in epitaxial silicene on Ag(111) surface are identified. In particular, the formation energies of point defects in Ag(111)-supported silicene sheets show an interesting dependence on the superstructures, which, in turn, may have implications for controlling the defect density during the synthesis of silicene. Through estimating the concentrations of various point defects in different silicene superstructures, the mystery of the defective appearance of 13 × 13 and 2 3 ×2 3 silicene in experiments is revealed, and 4×4 silicene sheet is thought to be the most suitable structure for future device applications. Disciplines Engineering | Physical Sciences and Mathematics2

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Section: Introductionmentioning

confidence: 99%

Point defects in epitaxial silicene on Ag(111) surfaces

Liu

Feng

et al. 2016

2D Mater.

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“…However, recent research efforts have been directed towards not only the synthesis of graphene-like materials, but also towards the functionalization of existing ultra-thin crystal structures. These recent studies have revealed some important results such as (i) tunable bandgap opening in graphene, [22][23][24][25][26][27] (ii) H-defect-induced magnetization of graphane, 27,28 (iii) bandgap engineering in silicene and germanene, [29][30][31] (iv) stability enhancement in h-BN, 32 and (v) tunable magnetic features in TMDs.…”

Section: Introductionmentioning

confidence: 99%

Single layer PbI₂: hydrogenation-driven reconstructions

Bacaksız

Şahin

2016

RSC Adv.

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By performing density functional theory-based calculations, we investigate how a hydrogen atom interacts with the surfaces of monolayer PbI 2 and how one-and two-side hydrogenation modifies its structural, electronic, and magnetic properties. Firstly, it was shown that the T-phase of single layer PbI 2 is energetically more favorable than the H-phase. It is found that hydrogenation of its surfaces is possible through the adsorption of hydrogen on the iodine sites. While H atoms do not form a particular bonding-type at low concentration, by increasing the number of hydrogenated I-sites well-ordered hydrogen patterns are formed on the PbI 2 matrix. In addition, we found that for one-side hydrogenation, the structure forms a (2 Â 1) Jahn-Teller type distorted structure and the bandgap is dramatically reduced compared to hydrogen-free single layer PbI 2 . Moreover, in the case of full hydrogenation, the structure also possesses another (2 Â 2) reconstruction with a reduction in the bandgap. The easily tunable electronic and structural properties of single layer PbI 2 controlled by hydrogenation reveal its potential uses in nanoscale semiconducting device applications.

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“…A larger U c implies a larger FM gap, which is confirmed by the first-principles calculation. 32 However, due to topological robustness of QAH states, we expect that the Berry curvature of the midgap bands and the corresponding Chern number would remain the same. The effects due to finite V A is examined in Fig.…”

Section: Summary and Discussionmentioning

confidence: 99%

“…For instance, the appearance of vacancy may modify electronic parameters locally. The perturbation may also lift up the σ bands at Γ, 32,[43][44][45] which may change the topology. However, a recent finding shows that hydrogenated graphene actually enhances SOC, 46 which can further stabilize the proposed QAH states.…”

Section: Summary and Discussionmentioning

confidence: 99%

Ferromagnetism and quantum anomalous Hall effect in one-side-saturated buckled honeycomb lattices

2014

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The recently synthesized silicene as well as theoretically discussed germanene are examples of buckled honeycomb structures. The buckled structures allow one to manipulate asymmetry between two underlying sublattices of honeycomb structures. Here by taking germanene as a prototype of buckled honeycomb lattices, we explore magnetism induced by breaking sublattice symmetry through saturating chemical bonds on one-side of the buckled honeycomb lattice. It is shown that when fractions of chemical bonds on one-side are saturated, two narrow bands always exist at half filling. Furthermore, the narrow bands generally support flat band ferromagnetism in the presence of the Hubbard U interaction. The induced magnetization is directly related to the saturation fraction and is thus controllable in magnitude through the saturation fraction. Most importantly, we find that depending on the saturation fraction, the ground state of an one-side saturated germanene may become a quantum anomalous Hall (QAH) insulator characterized by a Chern number that vanishes for larger magnetization. The non-vanishing Chern number for smaller magnetization implies that the associated quantum Hall effect tends to survive at high temperatures. Our findings provide a potential method to engineer buckled honeycomb structures into high-temperature QAH insulators.

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Induced ferromagnetism in one-side semihydrogenated silicene and germanene

Cited by 172 publications

References 46 publications

Point defects in epitaxial silicene on Ag(111) surfaces

Point defects in epitaxial silicene on Ag(111) surfaces

Single layer PbI₂: hydrogenation-driven reconstructions

Ferromagnetism and quantum anomalous Hall effect in one-side-saturated buckled honeycomb lattices

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Induced ferromagnetism in one-side semihydrogenated silicene and germanene

Cited by 172 publications

References 46 publications

Point defects in epitaxial silicene on Ag(111) surfaces

Point defects in epitaxial silicene on Ag(111) surfaces

Single layer PbI2: hydrogenation-driven reconstructions

Ferromagnetism and quantum anomalous Hall effect in one-side-saturated buckled honeycomb lattices

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Single layer PbI₂: hydrogenation-driven reconstructions