Structural Study of Si(111)($2\sqrt{3}\times 2\sqrt{3}$)R30°–Sn Surfaces

Ichikawa, T.; Cho, Kohei

doi:10.1143/jjap.42.5239

Cited by 13 publications

(16 citation statements)

References 2 publications

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“…The bright protusions shown by each tetramer are mainly associated with the two central Sn atoms of the tetramer that are ∼0.9-1.0 Å higher than the other Sn atoms. This explains the similarity of our images with those obtained for the Sn=Sið111Þ-2 ffiffi ffi 3 p surface, that presents a Sn double layer and a melting transition [39,40]. We can discard a Sn double layer for our system by measuring the step height between Sn=Sið111Þ∶B-2 ffiffi ffi 3 p and …”

supporting

confidence: 77%

Ultrafast Atomic Diffusion Inducing a Reversible(23×23)R30°↔(
Srour
¹
,
Trabada
²
,
Martínez
³

et al. 2015
Phys. Rev. Lett.
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5
0
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Dynamical phase transitions are a challenge to identify experimentally and describe theoretically. Here, we study a new reconstruction of Sn on silicon and observe a reversible transition where the surface unit cell divides its area by a factor of 4 at 250°C. This phase transition is explained by the 24-fold degeneracy of the ground state and a novel diffusive mechanism, where four Sn atoms arranged in a snakelike cluster wiggle at the surface exploring collectively the different quantum mechanical ground states.

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supporting

confidence: 77%

Ultrafast Atomic Diffusion Inducing a Reversible(23×23)R30°↔(
Srour
¹
,
Trabada
²
,
Martínez
³

et al. 2015
Phys. Rev. Lett.
7
0
5
0
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“…8. The melting transition on the Si͑111͒:Sn surface has been observed before in STM, 5 but the literature is lacking reports on the effect of the phase transition on the surface band structure. This paper presents a comparison between calculated atomic as well as electronic structures obtained from a 2 ͱ 3 model based on Ref.…”

Section: Introductionmentioning

confidence: 74%

“…However, only the top layer, with two pairs of atoms, could be resolved experimentally. Subsequent STM studies [3][4][5][6] have also failed to resolve the structure of the underlayer. The electronic structure of the 2 ͱ 3 surface has been investigated with scanning tunneling spectroscopy ͑STS͒, 4,6 angle-resolved photoelectron spectroscopy ͑ARPES͒, 6,7 and k-resolved inverse photoelectron spectroscopy ͑KRIPES͒ ͑Ref.…”

Section: Introductionmentioning

confidence: 99%

Atomic and electronic structures of the ordered23×23and molten1×1phase on the Si(111):Sn surface

et al. 2010

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The Si͑111͒ surface with an average coverage of slightly more than one monolayer of Sn, exhibits a 2 ͱ 3 ϫ 2 ͱ 3 reconstruction below 463 K. In the literature, atomic structure models with 13 or 14 Sn atoms in the unit cell have been proposed based on scanning tunneling microscopy ͑STM͒ results, even though only four Sn atoms could be resolved in the unit cell. This paper deals with two issues regarding this surface. First, high-resolution angle-resolved photoelectron spectroscopy ͑ARPES͒ and STM are used to test theoretically derived results from an atomic structure model comprised of 14 Sn atoms, ten in an underlayer and four in a top layer ͓C. Törnevik, M. Hammar, N. G. Nilsson, and S. A. Flodström, Phys. Rev. B 44, 13144 ͑1991͔͒. Low-temperature ARPES reveals six occupied surface states. The calculated surface band structure only reproduces some of these surface states. However, simulated STM images show that certain properties of the four atoms that are visible in STM are reproduced by the model. The electronic structure of the Sn atoms in the underlayer of the model does not correspond to any features seen in the ARPES results. STM images are presented which indicate the presence of a different underlayer consisting of eight Sn atoms, which is not compatible with the model. These results indicate that a revised model is called for. The second issue is the reversible transition from a 2 ͱ 3 ϫ 2 ͱ 3 phase below 463 K to a 1 ϫ 1 phase corresponding to a molten Sn layer, above that temperature. It is found that the surface band structure just below the transition temperature is quite similar to that at 100 K. The surface band structure undergoes a dramatic change at the transition. A strong surface state, showing a 1 ϫ 1 periodicity, can be detected above the transition temperature. This state resembles parts of two surface states which, already before the transition temperature is reached, have begun a transformation and lost much of their 2 ͱ 3 ϫ 2 ͱ 3 periodicities. Calculated surface band structures obtained from 1 ϫ 1 models with one monolayer of Sn are compared with ARPES and STM results. It is found that the strong surface state present above the transition temperature shows a dispersion similar to that of a calculated surface band originating from the Sn-Si interface with the Sn atoms in T 1 sites.

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“…This has proven to be a daunting task because the coverage is not precisely known. The 23 interface is known to consist of a double layer of Sn on Si(111) where the top layer is comprised of four atoms (one tetramer) per (23×23)R30° unit cell [17][18][19][20][21][22][23][24]. The unit cell is furthermore believed to contain a total of 13 or 14 Sn atoms [18][19][20][21][22][23], implying a coverage of 13/12 or 14/12 monolayers (ML), although some of the most recent models such as the ones by Eriksson [24] and by Srour et al [25] suggest a lower coverage (1 ML = 7.84 ×10 14 atoms per cm 2 which is the areal density of Si atoms in the Si(111) plane).…”

Section: Introductionmentioning

confidence: 99%

“…The 23 interface is known to consist of a double layer of Sn on Si(111) where the top layer is comprised of four atoms (one tetramer) per (23×23)R30° unit cell [17][18][19][20][21][22][23][24]. The unit cell is furthermore believed to contain a total of 13 or 14 Sn atoms [18][19][20][21][22][23], implying a coverage of 13/12 or 14/12 monolayers (ML), although some of the most recent models such as the ones by Eriksson [24] and by Srour et al [25] suggest a lower coverage (1 ML = 7.84 ×10 14 atoms per cm 2 which is the areal density of Si atoms in the Si(111) plane). This structure is particularly difficult to solve because the second Sn layer is mostly invisible to the STM whereas the large number of atoms per unit cell makes it very difficult to discriminate between models with say 12, 13, or 14 atoms per unit cell with the available surface analytical techniques.…”

Section: Introductionmentioning

confidence: 99%

Atomic and electronic structure of doped Si(111)(23×23)R30∘ -Sn interfaces

Ming

Huang

et al. 2018

Phys. Rev. B

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The hole doped Si(111)(23×23)R30⁰-Sn interface exhibits a symmetry-breaking insulator-insulator transition below 100 K that appears to be triggered by electron tunneling into the empty surface-state bands.No such transition is seen in electron-doped systems. To elucidate the nature and driving force of this phenomenon, the structure of the interface must be resolved. Here we report on an extensive experimental I INTRODUCTIONSurfaces and ultrathin metal/semiconductor interfaces are an interesting platform for studying phase transitions and emergent phenomena in two-dimensions (2D). In particular, adsorption of group III and group IV post-transition metal atoms on Si(111) and Ge(111) surfaces produces a variety of interesting phenomena such as Mott metal-insulator transitions [1-3], charge-ordering transitions [4][5][6][7][8], and even superconductivity [9][10][11][12][13]. Although the structural degrees of freedom of these systems are determined in large part by the underlying substrate, these systems are near-perfect 2D electron systems as the electronic interactions take place in one or several surface state bands that are generally decoupled from the 3D electronic structure of the underlying Si or Ge substrate.Notwithstanding their intellectual appeal, the electronic properties of surfaces and interfaces are difficult to control, other than through simple coverage control or change of substrate. For instance, strictly 3 2D systems such as exfoliated 2D materials, surfaces, and interfaces are all difficult to dope because the presence of dopants inevitably introduces structural disorder as the ionized dopant impurities, and the associated modulations of the potential energy landscape, become an integral part of the 2D electron system.In principle, this dilemma can be avoided by employing a modulation doping approach in which the chemical dopants are spatially separated from the 2D electron system [14], as is done in, e.g., semiconductor quantum well superlattices [14, 15] and layered perovskite materials [16]. In fact, most of the current emphasis on low-dimensional quantum matter phases involves mapping of the electronic phase diagrams of quasi 2D bulk materials as a function of doping level or chemical potential. However, efforts to systematically control the electronic properties of surfaces and interfaces are largely undeveloped, suggesting that many interesting 2D phases of matter are still awaiting experimental discovery.Using the modulation doping concept, we recently uncovered a novel equilibrium phase in a hole-doped bilayer of Sn on p-type Si(111) [17]. The holes originate from the boron dopants inside the bulk substrate.The formation of this broken symmetry phase appears to be triggered by electrons tunneling from the tip of a scanning tunneling microscope (STM) into the sample, and sets in below 100 K. No such transition is seen on n-type Si suggesting that the high-symmetry phase is the ground state for the n-type system. Scanning Tunneling Microscopy (STM) images of the high-symmetry phase orSi...

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Structural Study of Si(111)($2\sqrt{3}\times 2\sqrt{3}$)R30°–Sn Surfaces

Cited by 13 publications

References 2 publications

Ultrafast Atomic Diffusion Inducing a Reversible(23×23)R30°↔(
Srour
¹
,
Trabada
²
,
Martínez
³

et al. 2015
Phys. Rev. Lett.
7
0
5
0
View full text Add to dashboard Cite

Ultrafast Atomic Diffusion Inducing a Reversible(23×23)R30°↔(
Srour
¹
,
Trabada
²
,
Martínez
³

et al. 2015
Phys. Rev. Lett.
7
0
5
0
View full text Add to dashboard Cite

Atomic and electronic structures of the ordered23×23and molten1×1phase on the Si(111):Sn surface

Atomic and electronic structure of doped Si(111)(23×23)R30∘ -Sn interfaces

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Structural Study of Si(111)($2\sqrt{3}\times 2\sqrt{3}$)R30°–Sn Surfaces

Cited by 13 publications

References 2 publications

Ultrafast Atomic Diffusion Inducing a Reversible(23×23)R30°↔(Srour1, Trabada2, Martínez3 et al. 2015Phys. Rev. Lett.7050View full textAdd to dashboardCite

Ultrafast Atomic Diffusion Inducing a Reversible(23×23)R30°↔(Srour1, Trabada2, Martínez3 et al. 2015Phys. Rev. Lett.7050View full textAdd to dashboardCite

Atomic and electronic structures of the ordered23×23and molten1×1phase on the Si(111):Sn surface

Atomic and electronic structure of doped Si(111)(23×23)R30∘ -Sn interfaces

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Ultrafast Atomic Diffusion Inducing a Reversible(23×23)R30°↔(
Srour
¹
,
Trabada
²
,
Martínez
³

et al. 2015
Phys. Rev. Lett.
7
0
5
0
View full text Add to dashboard Cite

Ultrafast Atomic Diffusion Inducing a Reversible(23×23)R30°↔(
Srour
¹
,
Trabada
²
,
Martínez
³

et al. 2015
Phys. Rev. Lett.
7
0
5
0
View full text Add to dashboard Cite