Hostname: page-component-76fb5796d-22dnz Total loading time: 0 Render date: 2024-04-26T14:12:37.034Z Has data issue: false hasContentIssue false
  • English
  • Français

Floppy modes and the Boson peak in crystalline and amorphous silicates: an inelastic neutron scattering study

Published online by Cambridge University Press:  05 July 2018

M. J. Harris ,
M. T. Dove  and
J. M. Parker
M. J. Harris
Affiliation:
ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK
M. T. Dove*
Affiliation:
Mineral Physics Group, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
J. M. Parker
Affiliation:
Department of Engineering Materials, Sheffield University, Mappin Street, Sheffield S1 3JD, UK
*
* E-mail: martin@esc.cam.ac.uk
Get access Rights & Permissions [Opens in a new window]

Abstract

We present the results of an inelastic neutron scattering study of a crystalline polymorph of SiO2 (α-quartz), and a number of silicate glasses (pure silica, SiO2, and three glasses in the alkali series (K,Li)2Si2O5). We demonstrate the presence of the Boson peak in the inelastic spectra of the crystalline and amorphous materials and argue that it arises simply from the dispersion characteristics of transverse acoustic modes. Furthermore, we investigate the role of the lower-energy floppy modes in the inelastic spectra, and show that they are controlled by chemical effects.

Keywords

floppy modesBoson peaksilicatesneutron scatteringinelastic spectra
Type
Research Article
Information
Mineralogical Magazine , Volume 64 , Issue 3 , June 2000 , pp. 435 - 440
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2000

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Buchenau, U., Zhou, H.M., Nucker, N., Gilroy, K.S. and Phillips, W.A. (1987) Structural relaxation in vitreous silica. Phys. Rev. Lett., 60, 1318–21.CrossRefGoogle Scholar
Dove, M.T., Harris, M.J., Hannon, A.C., Parker, J.M., Swanson, I.P. and Gambhir, M. (1997) Floppy modes in crystalline and amorphous silicates. Phys. Rev. Lett., 78, 1070–3.CrossRefGoogle Scholar
Elliott, S.R. (1996) Comment on ‘Phonons in glasses: Numerical simulations and phenomenol ogical theory’. Phys. Rev. Lett., 77, 4105.CrossRefGoogle Scholar
Hannon, A.C., Vessal, B. and Parker, J.M. (1992) The structure of alkali silicate glasses. J. Non-Cryst. Solids, 150, 97–102.CrossRefGoogle Scholar
Leadbetter, A.J. (1969) Inelastic cold neutron scattering from different forms of silica. J. Chem. Phys., 51, 779.CrossRefGoogle Scholar
Phillips, W.A. (1987) Two-level states in glasses. Rep. Prog. Phys., 50, 1657–1708.CrossRefGoogle Scholar
Taraskin, S.N. and Elliot, S.R. (1997 a) Phonons in vitreous silica: dispersion and localization. Europhys. Lett., 39, 37–42.CrossRefGoogle Scholar
Taraskin, S.N. and Elliot, S.R. (1997 b) Nature of vibrational excitations in vitreous silica. Phys. Rev. B, 56, 8605–22CrossRefGoogle Scholar