Low-frequency modes in vitreous silica

Buchenau, U.; Prager, M.; Nücker, N.; Dianoux, A.J.; Ahmad, Naveed; Phillips, W. A.

doi:10.1103/physrevb.34.5665

Cited by 560 publications

(315 citation statements)

References 28 publications

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“…These show a density of states g lib ( ) peaked at about 1 THz and correspond to librations of the CN group, whose presence serves to explain the peak in C P (T)/T 3 , the low-temperature specific heat, and the ''plateau'' in the thermal conductivity. Such ''additional harmonic excitations'' are also well known from studies on canonical glasses such as vitreous SiO 2 , 38 and indeed, show a peaked density of states at about 2 THz.…”

Section: ␤ Relaxationmentioning

confidence: 88%

Relaxational dynamics in the glassy, supercooled liquid, and orientationally disordered crystal phases of a polymorphic molecular material

et al. 1999

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The relaxational dynamics of the ambient pressure phases of ethyl alcohol are studied by means of measurements of frequency dependent dielectric susceptibility. A comparison of the ␣ relaxation in the supercooled liquid and in the rotator phase crystal indicates that the molecular rotational degrees of freedom are the dominant contribution to structural relaxation at temperatures near the glass transition, the flow processes having lesser importance. Below the glass transition a secondary ␤ relaxation is resolved for the orientational and structural glasses. Computer molecular-dynamics results suggest that localized molecular librations, strongly coupled to the low-frequency internal molecular motions, are responsible for this secondary relaxation. ͓S0163-1829͑99͒00914-5͔

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Section: ␤ Relaxationmentioning

confidence: 88%

Relaxational dynamics in the glassy, supercooled liquid, and orientationally disordered crystal phases of a polymorphic molecular material

et al. 1999

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“…The comparison with experimental results on other systems and with moleculardynamics simulations 7,8,23 suggests the interpretation of this low-frequency feature as the high-frequency evolution of the transverse-acoustic mode. 25 However, it should be noted that the density fluctuation modes loose their symmetry as the wave vector is increased, so that the longitudinal and transverse terms have not a well defined significance. Accordingly, the visibility of a transverse excitation in the intrinsically longitudinal density fluctuation spectra of a disordered system can be justified by the mixing phenomenon, 26 or, in other words, at high frequency the transverse dynamics acquire a longitudinal component, observable in the neutron and x-ray scattering experiments.…”

Section: Methodsmentioning

confidence: 99%

Neutron scattering investigation of high-frequency dynamics in glassy glucose

et al. 2012

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The vibrational dynamics of vitreous glucose has been investigated by means of inelastic neutron scattering experiments, exploiting the coherent scattering cross section of deuterium in a fully deuterated sample and the high incoherent scattering cross section of hydrogen in a hydrogenated sample. The first part of the experiment allowed a rather detailed investigation of the collective dynamics in the THz range. The second part of the experiment was used to derive some information on the vibrational density of states of the system. The experiment confirms the presence of a propagating vibrational mode which is the natural extension at THz frequencies of the lower frequencies longitudinal sound mode. In addition, a second mode is also observed at a lower and almost constant frequency, showing an increasing intensity on reducing the wavelength. By comparing the dispersion relations of these collective modes to the experimental density of states, a possible relation between the low frequency mode and the well known excess of low frequency modes, that is, the boson peak, is identified.

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“…While this effect is in some ways analogous to the coupling with phonons in crystals, one cannot expect it to have the same dependence on the magnetic field and temperature due to a different density of states of vibrational modes in the amorphous medium [28]. We therefore include free parameters l and m in Eq.…”

mentioning

confidence: 99%

Efficient and long-lived Zeeman-sublevel atomic population storage in an erbium-doped glass fiber

et al. 2015

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Long-lived population storage in optically pumped levels of rare-earth ions doped into solids, referred to as persistent spectral hole burning, is of significant fundamental and technological interest. However, the demonstration of deep and persistent holes in rare-earth ion doped amorphous hosts, e.g. glasses, has remained an open challenge since many decades -a fact that motivates our work towards a better understanding of the interaction between impurities and vibrational modes in glasses.Here we report the first observation and detailed characterization of such holes in an erbium-doped silica glass fiber cooled to below 1 K. We demonstrate population storage in electronic Zeemansublevels of the erbium ground state with lifetimes up to 30 seconds and 80% spin polarization. In addition to its fundamental aspect, our investigation reveals a potential technological application of rare-earth ion doped amorphous materials, including at telecommunication wavelength.

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Low-frequency modes in vitreous silica

Cited by 560 publications

References 28 publications

Relaxational dynamics in the glassy, supercooled liquid, and orientationally disordered crystal phases of a polymorphic molecular material

Relaxational dynamics in the glassy, supercooled liquid, and orientationally disordered crystal phases of a polymorphic molecular material

Neutron scattering investigation of high-frequency dynamics in glassy glucose

Efficient and long-lived Zeeman-sublevel atomic population storage in an erbium-doped glass fiber

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