Kagome-like silicene: A novel exotic form of two-dimensional epitaxial silicon

Sassa, Yasmine; Johansson, Fredrik; Lindblad, Andreas; Yazdi, Milad Ghadami; Simonov, Konstantin A.; Weissenrieder, Jonas; Muntwiler, Matthias; İyikanat, Fadıl; Şahin, Hasan; Angot, Thierry; Salomon, Éric; Lay, G. Le

doi:10.1016/j.apsusc.2020.147195

Cited by 23 publications

(25 citation statements)

References 40 publications

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“…The bond length of b 2 (2.25 Å) is close to that of the sp 2 /sp 3 -hybridized bond (2.28 Å) in the honeycomb silicene, while that of b 1 (2.33 Å) is comparable in length with the sp 3 -hybridized bond (2.35 Å) in the bulk silicon, indicating that the components of sp 3 hybridization are indeed enhanced in the hhk-silicene. Note that a kagome-like lattice of silicene was recently synthesized on Al (111) substrates . First-principles molecular dynamics study predicted that Al (111) surface is also suitable for growing both honeycomb and polygonal silicene .…”

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confidence: 99%

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Semiconducting Silicene: A Two-Dimensional Silicon Allotrope with Hybrid Honeycomb-Kagome Lattice

Sang

Wang

Wei

et al. 2021

ACS Materials Lett.

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Silicene is recognized as a promising candidate of two-dimensional (2D) materials replacing bulk silicon in the post-CMOS era, because of its compatibility with silicon-based technologies. However, the Dirac-cone band structure, because of the honeycomb lattice, prevents pristine silicene from being applied as a semiconductor in electronic devices. Here, we propose a 2D-silicon semiconductor by introducing kagome topology into the honeycomb lattice, i.e., a hybrid honeycomb-kagome (hhk) structure that is referenced as hhk-silicene. Our first-principles calculations demonstrate the high geometric stability and excellent semiconducting properties of the hhk-silicene, which opens up an electronic bandgap comparable to that of the bulk silicon and bears an electron mobility as high as that of the honeycomb silicene. By designing a field-effect transistor based on the hhk-silicene, giant negative differential resistance and switching performance fulfilling the requirements of ITRS (International Technology Roadmap for Semiconductors) are predicted. This work opens up the possibility of rational design of 2D-silicon semiconductors by focusing on the topological lattice structures.

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confidence: 99%

“…Note that a kagome-like lattice of silicene was recently synthesized on Al (111) substrates. 31 First-principles molecular dynamics study predicted that Al (111) surface is also suitable for growing both honeycomb and polygonal silicene. 32 Thus, the hhk-silicene may be experimentally realized on the Al(111) surface (or similar substrates) in future studies.…”

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confidence: 99%

Semiconducting Silicene: A Two-Dimensional Silicon Allotrope with Hybrid Honeycomb-Kagome Lattice

Sang

Wang

Wei

et al. 2021

ACS Materials Lett.

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“…Interestingly, the 3 × 3 Ge adlayers show similar AA like features and atomic scale defects to those observed for the √3 × √3 rot 30° structure on Si(111) [ 144 ] and suggest similar behavior likely related to stresses in the adlayer. The 3 × 3 Ge and Si on Al(111) systems are both metallic [ 140–143 ] with calculations for the Ge/Al system showing evidence of extra charge at the adlayer–substrate interface. [ 143 ] This suggests an eigenstate of these systems that may correspond to an additional surface state, now a resonance on the metallic substrate, that may correspond to the FSS arising between the 7 × 7 ad‐layer and substrate.…”

Section: Analysis and Further Discussionmentioning

confidence: 99%

“…Recent studies of 3 Â 3 Si or Ge on Al(111) [140][141][142][143][144] are also systems with smaller unit cells that may allow DFT calculations using improved functionals. In addition, if thicker slabs are used, the metallic screening may minimize dipole contributions in a slab calculation.…”

Section: Related Silicon Systems That May Provide Further Insightmentioning

confidence: 99%

Evidence for “Unusual” Exchange–Correlation on Si(111) 7 × 7: Limitations of Density Functional Calculations for Charge Transfer Interactions on Semiconductor Surfaces

Demuth

2022

Physica Status Solidi (b)

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Electron–electron interactions on the Si (111) surface associated with inaccuracies in treating exchange and correlation are shown to be consistent with discrepancies found between density functional calculations and experimental measurements of the 7 × 7 surface. Here, the measured filled and empty surface states of the 7 × 7 surface are shown to be shifted away from one another relative to those predicted by effective one electron calculations using density functional theory. This corresponds to the “energy gap problem” widely known to occur in most bulk semiconductors arising from the approximate treatment of electron exchange–correlation, X–C, within such theoretical constructs. Considering more realistic treatments of X–C to correct these energy shifts leads to a different interpretation of the surface states and a new interaction that stabilizes the 7 × 7. This provides a physical basis for its unusual properties some of which are also observed in related 2D systems. The effects of various electron–electron interactions from these new interactions are considered and their behavior is used to explain the metallic nature of the 7 × 7 at 300 K.

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“…In particular, DB silicene has recently been predicted to constitute the true ground state of 2D silicon . Interestingly, the predicted electronic properties of DB silicene differ from those of free-standing silicene with a gap opening, a spin-polarized ground state, and a very low thermal conductivity. ,, Although dumbbell-like units have been proposed to form on an exotic 2D Si allotrope with a Kagome-like lattice different from the honeycomb structure expected for silicene, an experimental confirmation of the formation of DB silicene is still lacking. Indeed, it must be noted that although DB silicene has been proposed to explain the √3 × √3 phase of Si/Ag(111), a recent scanning tunneling microscopy (STM) and density-functional theory (DFT) study demonstrated that the observed phase corresponds to thicker films …”

Section: Introductionmentioning

confidence: 99%

Demonstration of the Existence of Dumbbell Silicene: A Stable Two-Dimensional Allotrope of Silicon

et al. 2021

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We report a combined experimental and theoretical study on the formation of dumbbell silicene structures on Ag(110). High-resolution scanning tunneling microscopy (STM) reveals a rich tapestry of adatom-free and -decorated bidimensional silicene phases covering the whole Ag(110) surface. The most thermodynamically stable silicene models obtained from densityfunctional theory (DFT) perfectly reproduce all features observed by STM. These phases correspond to different Si buckled honeycomb reconstructions ((13´4), c(18´4) and c(8´4)) composed of two periodic motifs common to all structural models. DFT calculations show that these reconstructions are stabilized by the presence of ordered arrays of Si adatoms adsorbed on top of silicene in a dumbbell configuration. Grazing incidence X-ray diffraction (GIXD) measurements confirm the growth of a dumbbell silicene layer. The structure factor values are well reproduced by a (13´4) model with 4 Si adatoms per unit cell and a slight distortion of the hexagonal unit cell. Our STM-DFT-GIXD study demonstrates the formation of dumbbell silicene, a theoretically predicted two-dimensional Si allotrope. This opens up perspectives for tuning the peculiar properties of silicene.

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Kagome-like silicene: A novel exotic form of two-dimensional epitaxial silicon

Cited by 23 publications

References 40 publications

Semiconducting Silicene: A Two-Dimensional Silicon Allotrope with Hybrid Honeycomb-Kagome Lattice

Semiconducting Silicene: A Two-Dimensional Silicon Allotrope with Hybrid Honeycomb-Kagome Lattice

Evidence for “Unusual” Exchange–Correlation on Si(111) 7 × 7: Limitations of Density Functional Calculations for Charge Transfer Interactions on Semiconductor Surfaces

Demonstration of the Existence of Dumbbell Silicene: A Stable Two-Dimensional Allotrope of Silicon

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