![]() ![]() ![]() Thermal conductivity and specific heat of noncrystalline solids. in Encyclopedia of Materials: Science and Technology 194–197 (Elsevier, 2001). in Encyclopedia of Materials: Science and Technology 212–215 (Elsevier, 2001). Amorphous materials: low-frequency vibrations. A unified model for the low-energy vibrational behaviour of amorphous solids. Collective nature of the boson peak and universal transboson dynamics of glasses. The nature of boson peak in Raman scattering in glasses. Furthermore, we present a heterogeneous-elastic theory calculation in two dimensions, which shows how the vibrational coupling of the transversal and flexural shear vertical phonon modes produces the boson peak in two-dimensional materials at a frequency similar to that of the bulk, in agreement with our measurements.ĭebye, P. We identify the boson peak as a wavenumber-independent spectral maximum at a frequency similar to what has been observed in and predicted for bulk vitreous silica. Here we present the experimental evidence of a boson peak in two-dimensional silica, through phonon spectra measured by means of inelastic helium-atom scattering. However, up until now, experimental observations in actual materials have not been possible due to the limited surface sensitivity of the methods usually applied to measure the boson peak. Two-dimensional random matrix models and molecular dynamics simulations predict that the boson peak should also be present in amorphous two-dimensional materials, a notion that is of practical importance because it leads to an excess of heat capacity and influences transport properties. ![]() It has been observed in a wide range of amorphous materials, from inorganic glasses to polymers. The boson peak is an excess in the phonon vibrational density of states relative to the Debye model. ![]()
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