Coulomb effects in disordered solids

Michael Thorpe, S. W. De Leeuw

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

We develop a general theory to calculate the vibrational response functions for disordered solids (such as glasses and disordered crystalline alloys) in the presence of long-range Coulomb forces. The longitudinal l() and transverse t() dielectric functions are shown to be related by l()/=2-/t(), where is the high-frequency electronic response. The Lyddane-Sachs-Teller relation is generalized for use in such systems. We derive sum rules involving moments that should be useful in interpreting experimental data. A general formulation is also set up for the density of states (2) and the neutron scattering law S(k,). These general results are illustrated by calculating these response functions for a model AX2 glass that roughly corresponds to vitreous silica. A periodic random network with 1536 ions in each supercell is constructed. The response functions are found using the equation-of-motion method with the Coulomb sums included explicitly using the Ewald method. The (bare) transverse response shows a rather broad optic peak whereas the longitudinal response (which is sensitive to the depolarizing field) has a sharper response at a higher frequency.

Original languageEnglish (US)
Pages (from-to)8490-8505
Number of pages16
JournalPhysical Review B
Volume33
Issue number12
DOIs
StatePublished - 1986
Externally publishedYes

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Glass
Fused silica
Neutron scattering
Equations of motion
Optics
Ions
Crystalline materials
glass
sum rules
equations of motion
neutron scattering
optics
silicon dioxide
moments
formulations
electronics
ions

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Coulomb effects in disordered solids. / Thorpe, Michael; De Leeuw, S. W.

In: Physical Review B, Vol. 33, No. 12, 1986, p. 8490-8505.

Research output: Contribution to journalArticle

Thorpe, M & De Leeuw, SW 1986, 'Coulomb effects in disordered solids', Physical Review B, vol. 33, no. 12, pp. 8490-8505. https://doi.org/10.1103/PhysRevB.33.8490
Thorpe, Michael ; De Leeuw, S. W. / Coulomb effects in disordered solids. In: Physical Review B. 1986 ; Vol. 33, No. 12. pp. 8490-8505.
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