Electron correlation effects in transport and tunneling spectroscopy of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi mathvariant="normal">Si</mml:mi><mml:mo>(</mml:mo><mml:mn>111</mml:mn><mml:mo>)</mml:mo><mml:mtext>−</mml:mtext><mml:mrow><mml:mn>7</mml:mn><mml:mo>×</mml:mo><mml:mn>7</mml:mn></mml:mrow></mml:math>surface

Odobescu, A. B.; Maizlakh, A. A.; Zaĭtsev-Zotov, S. V.

doi:10.1103/physrevb.92.165313

Cited by 12 publications

(24 citation statements)

References 22 publications

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“…Peaks in the density of states for bias voltages of −0.3, −0.8, −1.5, and −2.3 V, as well as peaks for empty states +0.3 V and +0.8 V, are observed. Similar peaks were observed by many groups [21,24,[32][33][34][35][36][37], and they are usually denoted as S 1 = −0.3 eV, S 2 = −0.8 eV, and S 3 = −1.4 eV; we also observed a state at −2.3 eV, which was detected by the XPS method [38]. Some authors associate certain peaks in the density of state spectrum with specific atoms on the surface (7 × 7), for example, peaks at −0.3 and + 0.3 V are associated with adatoms [21,32], and the peak at −0.8 V is associated with rest atoms [32,37], that is, they are considered in the framework of the approximation of the local density of electronic states of a given atom.…”

Section: Sts Of the Si (111)-(7 × 7) And Impact Of Nh 3 Adsorptionsupporting

confidence: 86%

Van der Waals and Graphene-Like Layers of Silicon Nitride and Aluminum Nitride

Мансуров¹,

Galitsyn²,

Малин³

et al. 2019

2D Materials

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A systematic study of kinetics and thermodynamics of Si (111) surface nitridation under ammonia exposure is presented. The appeared silicon nitride (8 × 8) structure is found to be a metastable phase. Experimental evidences of graphenelike nature of the silicon nitride (8 × 8) structure are presented. Interlayer spacings in the (SiN) 2 (AlN) 4 structure on the Si (111) surface are found equal to 3.3 Å in SiN and 2.86 Å in AlN. These interlayer spacings correspond to weak van der Waals interaction between layers. In contrast to the widely accepted model of a surface structure (8 × 8) as monolayer of β-Si 3 N 4 on Si (111) surface, we propose a new graphene-like Si 3 N 4 (g-Si 3 N 3 and/or g-Si 3 N 4) model for the (8 × 8) structure. It is revealed that the deposition of Al atoms on top of a highly ordered (8 × 8) structure results in graphene-like AlN (g-AlN) layers formation. The g-AlN lattice constant of 3.08 Å is found in a good agreement with the ab initio calculations. A transformation of the g-AlN to the bulk-like wurtzite AlN is analyzed.

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Section: Sts Of the Si (111)-(7 × 7) And Impact Of Nh 3 Adsorptionsupporting

confidence: 86%

Van der Waals and Graphene-Like Layers of Silicon Nitride and Aluminum Nitride

Мансуров¹,

Galitsyn²,

Малин³

et al. 2019

2D Materials

View full text Add to dashboard Cite

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“…As noted previously, this gap differs in highly doped samples and requires low‐doped samples to reflect the intrinsic surface properties. [ 11,12 ] A simple physical model can account for this based on the nodal properties of the resonance states that occur on the two sides of the 7 × 7 unit cell. Each side is referred to as “nano” cell and has 3 m symmetry.…”

Section: Discussionmentioning

confidence: 99%

“…The occupation of this higher state will change the “composition” of this adatom's CD and change its shape. Presumably, the higher symmetry R = 4 state closes the energy gap that existed at LT. [ 8–12 ]…”

Section: Discussionmentioning

confidence: 99%

“…The fit of the point contact measured conductivity to an [exp(− T ES / T )] 1/2 dependence over eight orders of magnitude is impressive but was not found to correspond to the temperature‐dependent changes observed in the tunneling gap. [ 12 ] In this expression T ES represents a parameter within the Efros–Shklovskii model of hopping conductivity (see ref. [12]).…”

Section: Discussionmentioning

confidence: 99%

“…[ 12 ] In this expression T ES represents a parameter within the Efros–Shklovskii model of hopping conductivity (see ref. [12]). This change in the tunneling gap has been explained within a model that includes Coulomb blockade [ 12 ] but may also be the result of a different two‐state system.…”

Section: Discussionmentioning

confidence: 99%

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Evidence for Symmetry Breaking in the Ground State of the Si(111)‐7 × 7: The Origin of Its Metal–Insulator Transition

Demuth

2020

Physica Status Solidi (b)

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Scanning tunneling microscopy (STM) of the Si(111)‐7 × 7 reconstructed surface at 5 K reveals that the highly symmetric STM image found at room temperature does not reflect the lowest energy, ground state of this system. Instead, the ground state has certain adatom charge densities distorted by ≈0.2–0.4 Å from the symmetric STM charge density positions observed at 300 K. This agrees with adatom ion core displacements in both a Patterson map and two additional phase‐reconstructed atom maps. Such ion core distortions are consistent with the Jahn–Teller effect associated with the threefold mirror symmetry of the Si(111)‐7 × 7 and its antiphase, faulted structure. The nodal properties of the electronic states of an underlying 7 × 7 honeycomb that arise from threefold symmetry are determined from solutions of the 2D inhomogeneous Helmholtz equation, and provide insight to the observed temperature‐dependent charge density changes. It is shown that an excited state of the honeycomb cells of a Si(111)‐7 × 7 support the higher symmetry charge densities observed at room temperature and the presence of strong electron–phonon coupling. The role of symmetry and anharmonicity in defining the structure and electronic interactions in the Si(111)‐7 × 7 are discussed.

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Evidence for Symmetry Breaking in the Ground State of the Si(111)‐7 × 7: The Origin of Its Metal–Insulator Transition

Demuth

2020

Physica Status Solidi (b)

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The perspective and top view of an ideal room‐temperature unit cell of a new 5×5 honeycomb structure on Si(111), called the InterDigitated‐Faulted‐Adatom model (or DFA), are displayed on the frontispiece page. This 5×5 transforms at higher temperatures into a similar 7×7 DFA that is discussed by J. E. Demuth in article number http://doi.wiley.com/10.1002/pssb.202000229. The 7×7 exhibits many paradoxical properties unaccounted for within current effective one‐electron calculations. Evidence is presented for a Jahn–Teller distortion in its ground state and phonon‐assisted adatom charge density distortions with increasing temperature. The symmetry properties of this new class of structures and the formation of resonance surface states are shown to account for this unusual behavior.

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Electron correlation effects in transport and tunneling spectroscopy of theSi(111)−7×7surface

Cited by 12 publications

References 22 publications

Van der Waals and Graphene-Like Layers of Silicon Nitride and Aluminum Nitride

Van der Waals and Graphene-Like Layers of Silicon Nitride and Aluminum Nitride

Evidence for Symmetry Breaking in the Ground State of the Si(111)‐7 × 7: The Origin of Its Metal–Insulator Transition

Evidence for Symmetry Breaking in the Ground State of the Si(111)‐7 × 7: The Origin of Its Metal–Insulator Transition

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