The Raman Spectrum of Amorphous Tellurium

Brodsky, M. H.; Gambino, R. J.; Smith, J. E.; Yacoby, Y.

doi:10.1002/pssb.2220520229

Cited by 139 publications

(94 citation statements)

References 20 publications

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“…20 The cavity volume is unusually large (37% of the total), but the fraction is also large in liquid Te up to 970 K. Electron diffraction data 18 show that intrachain bonds are shorter (2.80Å at 283 K) than in trigonal Te (2.84Å), which is consistent with the shift to higher vibration frequencies observed in Raman spectroscopy (the dominant feature at 157 cm −1 is higher than any phonon frequency in the crystal) 13 and Mössbauer measurements. 12 The latter also provided evidence that dangling bonds at the chain ends were responsible for changes in the phonon frequencies.…”

Section: Discussion and Concluding Remarkssupporting

confidence: 66%

Structure and dynamics in amorphous tellurium and Tenclusters: A density functional study

Akola

Jones

2012

Phys. Rev. B

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Density functional/molecular dynamics simulations have been performed on amorphous tellurium (a meltquenched sample of 343 atoms at 300 K) and on Te clusters with up to 16 atoms. The former extend our calculations on liquid Te at 560, 625, 722, and 970 K [Phys. Rev. B 81, 094202 (2010)]. We discuss trends in structures (including those of other group-16 elements), electronic densities of states, and vibration frequencies. Chain structures are common in S and Se, but the chains in amorphous Te are short, and branching sites with threefold-coordinated atoms are common. The energy difference between two-and threefold local coordination depends sensitively on the exchange-correlation functional used. Cavities are characteristic of amorphous Te (37% of total volume), but are absent in crystalline (trigonal) Te.

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Section: Discussion and Concluding Remarkssupporting

confidence: 66%

Structure and dynamics in amorphous tellurium and Tenclusters: A density functional study

Akola

Jones

2012

Phys. Rev. B

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“…The main Raman band of vapor-deposited a-Te is at ∼157 cm −1 . 33 Despite having many vibrational modes (see Fig. 9), the Raman spectrum of GGT is very weak in the range 150-180 cm −1 .…”

Section: B Vibration Frequencies Raman Spectramentioning

confidence: 99%

Structure, electronic, and vibrational properties of glassy Ga11Ge11Te78: Experimentally constrained densi

et al. 2012

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The atomic structure and electronic and vibrational properties of glassy Ga 11 Ge 11 Te 78 have been studied by combining density functional (DF) simulations with x-ray (XRD) and neutron diffraction (ND), extended x-ray absorption fine structure (EXAFS), and Raman spectroscopies. The final DF structure (540 atoms) was refined using reverse Monte Carlo methods to reproduce the XRD and ND data as well as Ge and Ga K-edge EXAFS spectra, while maintaining a semiconducting band gap and a total energy close to the DF minimum. The local coordination of Ga is tetrahedral, while Ge has twice as many tetrahedral as defective octahedral configurations. The average coordination numbers are Ga, 4.1, Ge, 3.8, and Te, 2.6. The chemical bonding around Ga involves Ga 4s, Ga 4p, Te 5s, and Te 5p orbitals, and the bond strengths show bonding close to covalent, as in Ge. There are fewer Te chains and cavities than in amorphous Te, and a prepeak in the structure factor at 1.0Å −1 indicates medium-range order of the Ga/Ge network. Density functional calculations show that contributions of Te-Te, Ga-Te, and Ge-Te bonds dominate the experimental Raman spectra in the 110-150 cm −1 range.

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“…[10]. [19]. Depending on the degree of disorder (ratio of intermolecular to intramolecular interactions) this peak shifts continuously within the above wavenumber range.…”

Section: Structure and Vibrational Modes Of A-getementioning

confidence: 99%

Raman scattering study of the a-GeTe structure and possible mechanism for the amorphous to crystal transition

Andrikopoulos¹,

Yannopoulos²,

Voyiatzis³

et al. 2006

J. Phys.: Condens. Matter

206

167

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We report on an inelastic (Raman) light scattering study of the local structure of amorphous GeTe films. A detailed analysis of the temperature-reduced Raman spectra has shown that appreciable structural changes occur as a function of temperature. These changes involve modifications of atomic arrangements such as to facilitate the rapid amorphous-to-crystal transformation, which is the major advantage of phase-change materials used in optical data storage media. A particular structural model, supported by polarization analysis, is proposed being compatible with the experimental data as regards both the structure of a-GeTe and the crystallization transition. The remarkable difference between the Raman spectrum of the crystal and the glass can thus naturally be accounted for.

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The Raman Spectrum of Amorphous Tellurium

Cited by 139 publications

References 20 publications

Structure and dynamics in amorphous tellurium and Tenclusters: A density functional study

Structure and dynamics in amorphous tellurium and Tenclusters: A density functional study

Structure, electronic, and vibrational properties of glassy Ga11Ge11Te78: Experimentally constrained densi

Raman scattering study of the a-GeTe structure and possible mechanism for the amorphous to crystal transition

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