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Silica Dioxide

Crystal: SiO₂

Structure: Various, here: a = trigonal and b = hexagonal

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Mechanical and structural properties:

Cohesive energy:	eV
Lattice parameter:	Å
Density:	g/cm³

Stiffness constants: in 10¹¹ dynes/cm², at room temperature

	a	b
c₁₁:	8.76	11.66
c₁₂:	0.67	1.67
c₄₄:	5.72	3.606
c₃₃:	10.68	11.04

Fused quartz: third and fourth order elastic constants.:

K-i Kondo, S. Iio, A. Sowaoka, J. Appl. Phys. 52, 2827 (1981)

Poisson ratio:

Compressibility (in 10¹¹ dynes/cm²): a =0.297 b =0.200 Fused quartz: (Ref.1)

p₁₁: 7.8394

p₄₄: 3.1261

p₁₁1: 52.6

p₁₁₂: 23.9

p₁₂₃: 5.4

Debye temperature: 290 K for a , see also Ref.2

Melting temperature: see Ref.3

Neel temperature: K

Phonon spectrum discussed by: see Phys. Rev. B12, 4553 (1975) for a

Temperature dependence of phonons: See J. Phys. C15, 3821 (1982)

Phonon dispersion in quartz: See J. Phys. C13, 6607 (1980)

Transverse optic phonon T0 (k=0): see Phys. Rev. B11, 3944 (1975)

Longitude optic phonon L0 (k=0): see Phys. Rev. B13, 5525 (1976)

Gruneissen constant:

Polaron coupling constant: a = ( for m*=1 )

Ratio e*/e:

Electronic properties:

Band gap:

direct: eV.

indirect: eV.

Gap: eV.

First exciton: eV.

SiO2 absorption edge, exciton resonances:

R.B. Laughlin, Phys. Rev. B22, 3021 (1980) which gives: Band Gap Eg = 8.9 eV.

SiO2-polymorphs-Valence forces, lattice vibrations: See J. Chem. Phys. 68, 1531 (1978)

Valence bond forces: see Phys. Rev. B17, 2790 (1978)

Valence band density of states: Tagle et al., Surf. Sci. 81, 5189 (1979)

Electron levels: Phys. Rev. B10, 710 (1974)

Charge transport: see Nature 256, 12 (03/07/1975)

Electron: - band like

- small polaron in non-bonding orbital: ~0.6 eV. Ea

See Phys. Rev. Letters 27, 1560 (1971) for theory

Also: Appl. Phys. Letters 26, 436 (1975)

Free energy of SiO2 (vitreous, various models) relative to crystalline. Bond enthalpies: D.G. Howitt, D.K. McElfresh, Phys. Chem. Glasses 23, 107 (1982)

Band structure discussed by: Pantelides and Harrison, Phys. Rev.B13,2667 (1976)

Static dielectric constant: at 300K, for a quartz (Ref.4), // = 4.6368 and ^ = 4.5208

Optic dielectric constant: 2.40 for a

Linear dispersion of transverse phonons to 450 Ghz: Phys. Rev. B27, 5196 (1983)

Electron mobility:

Hole mobility:

Effective mass:

conduction band:

valence band:

Electron affinity: (in eV., from bottom of conduction band under vacuum)

SiO2 electron transport breakdown:

m(p)~ 1.3 m(o) seems the best

Ref.: D.K. Ferry, J. Appl. Phys. 50, 1422 (1979)

Spin-orbit coupling: (valence band)

Cation polarisation: Å^-3

Anion polarisation: Å^-3

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Other information:

Silica glass and force model: R.J. Bell, A. Dean, Phys. Chem. Glasses 18, 105 (1977)

High pressure behaviour of a -quartz SiO2 and nitrides of Si, Ge. Phases changes and compressibilities: L. Cartz, J.D. Jorgensen, J. Appl. Phys. 52, 237 (1981)

SiO2: thermal expansion of quartz: J Phys. C15, 4311 (1982)

Thermal conductivity of vitreous silica: D. Jones, W.A. Phillips, Phys. Rev. B27, 3891 (1983)

b -transition in quartz: T.A. Aslanyan et al., J.Phys. C16, 6705 (1983)

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References:

1. J. Appl. Phys. 49, 4776

2. Geophys. J. Roy. Astronom. Soc. 32, 15 (1973)

3. J. Geophys. Res. 81, 2453 (1976)

4. J. Appl. Phys. 45, 2852 (1974)

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