New insights into the lattice dynamics of<i>α</i>-quartz

Bosak, Alexeï; Krisch, M.; Chernyshov, Dmitry; Winkler, Björn; Milman, Victor; Refson, Keith; Schulze-Briese, Clemens

doi:10.1524/zkri.2012.1432

Cited by 23 publications

(23 citation statements)

References 29 publications

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“…Remarkably, even the tiniest details are reproduced by the DFPT calculations. The validity of the calculations was further confirmed exploring the inelastic scattering in selected directions (figure 6), including those of low symmetry, and measurements of powder inelastic spectra (not shown here, see [25]). …”

Section: α-Quartzmentioning

confidence: 63%

“…Considerable efforts were undertaken to link the properties of glasses to the properties of crystalline counter partners [23], and in this context the detailed knowledge of the lattice dynamics of different SiO 2 frameworks is very important. Combined studies by diffuse scattering, inelastic scattering and ab initio calculations were performed for three polymorphs, namely α-cristobalite [24], α-quartz [25] and coesite [26].…”

Section: Case Study: Covalent Framework Structures Of Siomentioning

confidence: 99%

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In-between Bragg reflections: thermal diffuse scattering and vibrational spectroscopy with x-rays

Bosak

Chernyshov

Wehinger

et al. 2015

J. Phys. D: Appl. Phys.

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In the last decade diffuse scattering studies re-gained their place in the domain of lattice dynamics studies. The use of thermal diffuse scattering becomes particularly efficient when coupled with vibrational spectroscopy, where inelastic x-ray scattering can be advantageous compared to inelastic neutron scattering, and state-of-the-art ab initio calculations. We present a brief summary of the experimental and theoretical background, give an overview of the principle experimental implementations, and discuss a representative set of examples of such a combined approach.

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Section: α-Quartzmentioning

confidence: 63%

Section: Case Study: Covalent Framework Structures Of Siomentioning

confidence: 99%

In-between Bragg reflections: thermal diffuse scattering and vibrational spectroscopy with x-rays

Bosak

Chernyshov

Wehinger

et al. 2015

J. Phys. D: Appl. Phys.

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“…The superconducting properties of the main sample used for this study were published elsewhere. 15,16 TDS experiments 17 at 77 K and room temperature were performed using a PILATUS 6M detector and a wavelength λ = 0.6966Å (see Fig. 1).…”

Section: Methodsmentioning

confidence: 99%

Anharmonic suppression of charge density waves in 2H-NbS2

et al. 2012

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The temperature dependence of the phonon spectrum in the superconducting transition-metal dichalcogenide 2H-NbS 2 is measured by diffuse and inelastic x-ray scattering. A deep, wide, and strongly temperature-dependent softening of the two lowest-energy longitudinal phonon bands appears along the M symmetry line in reciprocal space. In sharp contrast to the isoelectronic compound 2H-NbSe 2 , the soft phonons energies are finite, even at very low temperature, and no charge density wave instability occurs, in disagreement with harmonic ab initio calculations. We show that 2H-NbS 2 is at the verge of the charge density wave transition and its occurrence is only suppressed by the large anharmonic effects. Moreover, the anharmonicity and the electron phonon coupling both show a strong in-plane anisotropy.

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“…The inelastic x rays scattering spectra for the polycrystal were then computed in the one-phonon approximation (further details on the numerical calculation can be found in the Supplemental Material [42] and in Ref. [44]). …”

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confidence: 99%

Emergence of Crystal-like Atomic Dynamics in Glasses at the Nanometer Scale

et al. 2013

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The vibrational dynamics of a permanently densified silica glass is compared to the one of an -quartz polycrystal, the silica polymorph of the same density and local structure. The combined use of inelastic x-ray scattering experiments and ab initio numerical calculations provides compelling evidence of a transition, in the glass, from the isotropic elastic response at long wavelengths to a microscopic regime as the wavelength decreases below a characteristic length of a few nanometers, corresponding to about 20 interatomic distances. In the microscopic regime the glass vibrations closely resemble those of the polycrystal, with excitations related to the acoustic and optic modes of the crystal. A coherent description of the experimental results is obtained assuming that the elastic modulus of the glass presents spatial heterogeneities of an average size a $ =2. DOI: 10.1103/PhysRevLett.110.185503 PACS numbers: 63.50.Lm, 62.30.+d, 62.65.+k, 64.70.ph Amorphous solids lack the long-range translational periodicity of crystalline materials. Nevertheless, their structure presents a residual order on the short and medium ranges [1]. At short distances the structure can be characterized in terms of interatomic distances and bond-angles distribution. The medium-range order extends typically over a length D $ 2=ÁQ 0 of a few ($ 5) interatomic distances, as indicated by the width ÁQ 0 of the first sharp diffraction peak in the static structure factor, SðQÞ. The length scale of the nanometer is believed to be the relevant one to understand the phenomenology of the glass transition. In fact, close to the dynamical arrest, the atomic motion of a supercooled liquid is characterized by nanometer-sized regions where the molecules move cooperatively [2][3][4][5][6][7]. Recent numerical simulation studies [8][9][10] have also given some evidence of the presence of static correlation lengths of a size comparable to the dynamical correlations, by investigating either subtle structural order parameters [8] or point to set correlations [9,10]. However these quantities are not easily accessible experimentally, because they are not revealed by standard two-points correlation functions, such as the SðQÞ. Thereby a detailed description of the medium-range order in glasses is still missing.Only recently, the development of new experimental probes has given some evidence of the presence of atomic regions of nanometric size in a few amorphous materials. Local symmetries in a colloidal suspension have been detected by means of a cross correlation analysis using coherent x rays [11]. Subnanoscale-ordered regions originating from atomic polyhedra have also been detected in a metallic glass employing an electron nanoprobe supported by an ab initio molecular dynamics simulation [12]. On a similar glass a wide spatial distribution of the elastic modulus, on the length scale of the nanometer, has been detected by means of atomic force acoustic microscopy [13]. Here we employ an alternative way to gather information on the structure of the canon...

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New insights into the lattice dynamics ofα-quartz

Cited by 23 publications

References 29 publications

In-between Bragg reflections: thermal diffuse scattering and vibrational spectroscopy with x-rays

In-between Bragg reflections: thermal diffuse scattering and vibrational spectroscopy with x-rays

Anharmonic suppression of charge density waves in 2H-NbS2

Emergence of Crystal-like Atomic Dynamics in Glasses at the Nanometer Scale

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