Two-Level Systems and Excited-State Transitions in Fluorite Mixed Crystals and Silica Glass

Sa, FitzGerald; Ja, Campbell; Aj, Sievers

doi:10.1103/physrevlett.73.3105

Cited by 23 publications

(15 citation statements)

References 17 publications

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“…Firstly, although the relaxational͞vibrational intensity ratios of the two glasses are different, the resonant interaction at low frequencies is once again observed suggesting a universal behavior. Secondly, at about 15 cm 21 a crossover is observed, as in IR measurements reported recently in the same kind of glass [5]. Excited state transitions of the TLS have been postulated to explain this behavior.…”

supporting

confidence: 66%

“…Despite the lack of a precise microscopic model for the origin of the TLS, it is possible to explain, assuming a tunneling of atoms or groups of atoms, the specific glass properties for temperatures lower than a few K. At higher temperatures the model has been extended towards soft configurations [3], or overdamped TLS [4]. Recently excited states of TLS have been proposed as an interpretation of infrared (IR) data [5].…”

mentioning

confidence: 99%

“…3. Indeed the crossover from the resonant interaction regime to the thermal relaxation process has given rise to the introduction of conflicting models [19]: soft potential model [20], influence of higher excited levels of TLS [5], overdamping of TLS [4] have been considered. Hitherto only poor agreement has been found between theoretical predictions and experimental results at temperatures above a few kelvin.…”

mentioning

confidence: 99%

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Tunneling States and Resonant Light Interaction in an Oxide Glass

Terki

Pelous

1996

Phys. Rev. Lett.

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A light scattering study has been performed on two efficient Raman scattering optical glasses from 0.15 to 3 THz at low temperatures. In the low-frequency range, we found an increase of the scattered intensity below 10 K. In contrast to previous investigations, mainly in vitreous silica, which have found an absence of light scattering by resonant interaction with two-level systems in glasses, our results are in good agreement with theoretical predictions which assume a coupling of light with tunneling states. [S0031-9007(96)00687-4]

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supporting

confidence: 66%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Tunneling States and Resonant Light Interaction in an Oxide Glass

Terki

Pelous

1996

Phys. Rev. Lett.

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“…(62)) reproduces an ensemble of states both SWP and DWP, with a broad spectrum of barrier heights V and asymmetries ∆. Some TLS effects associated with excited-state transitions of TLS could be brought to the fore in some laboratory experiments (FitzGerald et al 1994;Sievers et al 1998) on a number of mixed fluorite crystals and soda-lime silica glass. However, these effects can only be seen in a narrow temperature range, roughly below 15 K, before relaxation processes dominate at higher temperatures.…”

Section: Tls Absorption 431 Phenomenological Tls Theorymentioning

confidence: 99%

Far-infrared to millimeter astrophysical dust emission

Meny¹,

Gromov

Boudet³

et al. 2007

A&A

161

206

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Aims. We propose a new description of astronomical dust emission in the spectral region from the far-infrared to millimeter wavelengths. Methods. Unlike previous classical models, this description explicitly incorporates the effect of the disordered internal structure of amorphous dust grains. Our model is based on results from solid state physics used to interpret laboratory data. The model takes into account the effect of absorption by disordered charge distribution, as well as the effect of absorption by localized two level systems. Results. We review constraints on the various free parameters of the model from theory and laboratory experimental data. We show that, for realistic values of the free parameters, the shape of the emission spectrum will exhibit very broad structures whose shape will change in a non trivial way with the temperature of dust grains. The spectral shape also depends upon the parameters describing the internal structure of the grains. This opens new perspectives for identifying the nature of astronomical dust from the observed shape of the FIR/mm emission spectrum. A companion paper will provide an explicit comparison of the model with astronomical data.

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“…4,5 Although several experimental investigations clearly demonstrated the existence of the tunneling states in glasses, the nature of the tunneling states has yet to be identified. 6,7 There are indications that the tunneling entities are associated with a group of atoms, and may be influenced by the structural configuration which is frozen into the material at the glass transition. 8,9 This speculation has lead to a number of theoretical models which intend to attribute the existence of TLS's to the structures and the properties of glasses near the glass transitions.…”

mentioning

confidence: 99%

Correlation between density of tunneling states and fragility of glasses

Zhu

1996

Phys. Rev. B

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Evidence of a correlation between the density of tunneling states of two-level systems and the fragility for a variety of glasses is presented. More fragile glasses tend to have a higher excess low-temperature (TϽ1 K͒ specific heat and thus a higher density of tunneling states. This correlation is consistent with a picture which connects the fragility of glasses to the topology on their potential energy hypersurfaces in configuration space.

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Two-Level Systems and Excited-State Transitions in Fluorite Mixed Crystals and Silica Glass

Cited by 23 publications

References 17 publications

Tunneling States and Resonant Light Interaction in an Oxide Glass

Tunneling States and Resonant Light Interaction in an Oxide Glass

Far-infrared to millimeter astrophysical dust emission

Correlation between density of tunneling states and fragility of glasses

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