Evidences of the existence of SiTe2 crystalline phase and a proposed new Si–Te phase diagram

Mishra, R.; Mishra, Prerna; Phapale, S.; Babu, P. D.; Sastry, P. U.; Ravikumar, G.; Yadav, Ashok K.

doi:10.1016/j.jssc.2016.02.021

Cited by 24 publications

(17 citation statements)

References 8 publications

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“…It is isostructural to CdI 2 (C6 structure) 44 where sheets are stacked directly above each other. The same structure is found at ambient pressure in chemically similar systems with heavier atoms such as SnS 2 45 or SiTe 2 46 as well as in several other chalcogenides, iodides, chlorides and bromides 44,[47][48][49][50] , or even in BeH 2 51 . The second lowest-enthalpy phase P 6 3 mc contains two layers per unit cell which are mutually staggered and reflected with respect to each other -Fig.…”

Section: A Phases Of Sis2 Above the Tetrahedral Regimesupporting

confidence: 60%

Creating new layered structures at high pressures: SiS2

Plašienka

Martoňák

Tosatti

2016

Sci Rep

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Old and novel layered structures are attracting increasing attention for their physical, electronic, and frictional properties. SiS2, isoelectronic to SiO2, CO2 and CS2, is a material whose phases known experimentally up to 6 GPa exhibit 1D chain-like, 2D layered and 3D tetrahedral structures. We present highly predictive ab initio calculations combined with evolutionary structure search and molecular dynamics simulations of the structural and electronic evolution of SiS2 up to 100 GPa. A highly stable CdI2-type layered structure, which is octahedrally coordinated with space group surprisingly appears between 4 and up to at least 100 GPa. The tetrahedral-octahedral switch is naturally expected upon compression, unlike the layered character realized here by edge-sharing SiS6 octahedral units connecting within but not among sheets. The predicted phase is semiconducting with an indirect band gap of about 2 eV at 10 GPa, decreasing under pressure until metallization around 40 GPa. The robustness of the layered phase suggests possible recovery at ambient pressure, where calculated phonon spectra indicate dynamical stability. Even a single monolayer is found to be dynamically stable in isolation, suggesting that it could possibly be sheared or exfoliated from bulk -SiS2.

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Section: A Phases Of Sis2 Above the Tetrahedral Regimesupporting

confidence: 60%

Creating new layered structures at high pressures: SiS2

Plašienka

Martoňák

Tosatti

2016

Sci Rep

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“…First-principles calculations and experiments show that it possesses anisotropic optical properties. , Experiments by Wang et al show that its optoelectronic properties can be modified through doping and intercalation of Ge and Cu without altering the fundamental host lattice . Other members of the Si–Te family, such as SiTe and SiTe 2 , are also confirmed and have shown interesting properties. − A recent theoretical investigation discovered a novel structure of SiTe 2 that is more stable than the CdI 2 type that is common in MX 2 compounds, which again manifests the uniqueness of this material system.…”

Section: Introductionmentioning

confidence: 99%

Pressure-Induced Insulator–Metal Transition in Silicon Telluride from First-Principles Calculations

Bhattarai

Shen

2021

J. Phys. Chem. C

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Silicon telluride (Si2Te3) is a two-dimensional semiconductor with unique structural properties due to the size contrast between Si and Te atoms. A recent experiment shows that the material turns metallic under hydrostatic pressure, while the lattice structure of the metallic phase remains to be identified. In this paper, we propose two metallic phases, M1 and M2, of Si2Te3 using the evolution algorithm and firstprinciples density functional theory (DFT) calculations. Unlike the presence of Si-Si dimers in the semiconducting (SC) phase, both M1 and M2 phases have individual Si atoms, which play important roles in the metallicity. Analysis of structural properties, electronic properties, dynamical as well as thermal stability is performed. The energies of these new structures are compared with the SC phase under the subsequent hydrostatic pressure up to 12 GPa. The results show that M1 and M2 phases have lower energies under high pressure, thus elucidating the appearance of the metallic phase of Si2Te3. In addition, the external pressure causes the SC phase to have an indirect-direct-indirect bandgap transition. Analysis of Raman spectra of the SC phase at a different pressure shows the shifting of the major Raman peaks, and finally disappearing confirms the phase transition. The results are in good agreement with the experimental observations. The understanding of the insulator-metal phase transition increases the potential usefulness of the material system.

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“… 24 The other Si x –Te y compound is silicon ditelluride (SiTe 2 ), 31 − 34 whose electrical, thermal, and magnetic properties have recently drawn a number of investigations. 35 − 37 The crystal structure of SiTe 2 is identified to be the CdI 2 -type 34 , 38 as other 2D IV–VI 2 materials, although it was suggested that it might also exist in the Si 2 Te 3 structure with Si deficiency. 39 …”

Section: Introductionmentioning

confidence: 99%

Predicting a Novel Phase of 2D SiTe₂

Bhattarai

Shen

2020

ACS Omega

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Layered IV–VI 2 compounds often exist in a CdI 2 structure. Using the evolution algorithm and first-principles calculations, we predict a novel layered structure of silicon ditelluride (SiTe 2 ) that is more stable than the CdI 2 phase. The structure has a triclinic unit cell in its bulk form. The atomic arrangement indicates the competition between the Si atoms’ tendency to form tetrahedral bonds and the Te atoms’ tendency to form hexagonal close-packing. The electronic and vibrational properties of the predicted phase are investigated. The effective mass of an electron is small among two-dimensional (2D) semiconductors, which is beneficial for applications such as field-effect transistors. The vibrational Raman and IR spectra are calculated to facilitate future experimental investigations.

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Evidences of the existence of SiTe2 crystalline phase and a proposed new Si–Te phase diagram

Cited by 24 publications

References 8 publications

Creating new layered structures at high pressures: SiS2

Creating new layered structures at high pressures: SiS2

Pressure-Induced Insulator–Metal Transition in Silicon Telluride from First-Principles Calculations

Predicting a Novel Phase of 2D SiTe₂

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Evidences of the existence of SiTe2 crystalline phase and a proposed new Si–Te phase diagram

Cited by 24 publications

References 8 publications

Creating new layered structures at high pressures: SiS2

Creating new layered structures at high pressures: SiS2

Pressure-Induced Insulator–Metal Transition in Silicon Telluride from First-Principles Calculations

Predicting a Novel Phase of 2D SiTe2

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Predicting a Novel Phase of 2D SiTe₂