Disorder-induced vibrational anomalies from crystalline to amorphous solids

Zhang, Ling; Wang, Yinqiao; Chen, Yangrui; Shang, Jun; Sun, Aile; Sun, Xulai; Yu, Shuchang; Zheng, Jie; Wang, Yujie; Schirmacher, Walter; Zhang, Jie

doi:10.1103/physrevresearch.3.l032067

Cited by 5 publications

(5 citation statements)

References 60 publications

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“…Specifically, as previously said, the low and weakly temperature dependent thermal conductivity in glasses has been associated to the existence of a strong phonon scattering due to the intrinsic disorder. Such regime, characterized by Γ FWHM ∝ (ℏω) 4 , has been reported in some glasses at energies corresponding to the deviation of the GVDOS from the Debye behavior and has lately been ascribed mostly to the force-constant disorder at a nanometric lengthscale [13][14][15] . Interestingly, the same phenomenology arises in random matrix approaches, which model the vibrational properties of a glass through a random network of force-constants over a regular lattice, quite similarly to the case of our HEA 61,62 .…”

Section: Discussionmentioning

confidence: 90%

“…In glasses, the emergence of a low and weakly temperature dependent lattice thermal conductivity has been ascribed to a strong phonon scattering due to the intrinsic disorder, which includes topological, mass and force-constant disorder 11 – 13 . While there are indications that force-constant disorder at the nanoscale is mainly responsible for such strong scattering 13 – 15 , it is experimentally impossible to separate the effect of the different kinds of disorder in glasses, as they are entangled. The situation is different in random alloys, where the topological disorder is absent and is replaced only by a local strain due to the atomic size disorder.…”

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Phonon behavior in a random solid solution: a lattice dynamics study on the high-entropy alloy FeCoCrMnNi

et al. 2022

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High-Entropy Alloys (HEAs) are a new family of crystalline random alloys with four or more elements in a simple unit cell, at the forefront of materials research for their exceptional mechanical properties. Their strong chemical disorder leads to mass and force-constant fluctuations which are expected to strongly reduce phonon lifetime, responsible for thermal transport, similarly to glasses. Still, the long range order would associate HEAs to crystals with a complex disordered unit cell. These two families of materials, however, exhibit very different phonon dynamics, still leading to similar thermal properties. The question arises on the positioning of HEAs in this context. Here we present an exhaustive experimental investigation of the lattice dynamics in a HEA, Fe20Co20Cr20Mn20Ni20, using inelastic neutron and X-ray scattering. We demonstrate that HEAs present unique phonon dynamics at the frontier between fully disordered and ordered materials, characterized by long-propagating acoustic phonons in the whole Brillouin zone.

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Section: Discussionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Phonon behavior in a random solid solution: a lattice dynamics study on the high-entropy alloy FeCoCrMnNi

et al. 2022

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“…On the contrary, amorphous materials have an excess of low-frequency modes over Debye's prediction that induces a peak in the reduced density of states D(ω)/ω d−1 at the Boson peak frequency, ω bp , in the terahertz regime for molecular solids. Previous works have attributed the Boson peak to elastic disorder [3][4][5], localized harmonic/anharmonic vibrations [6][7][8][9], broadening of van Hove singularities [10,11] (but see [12]). In addition, in amorphous solids the low-frequency excitations comprises both phononic-like modes and additional quasi-localized vibrational modes (QLMs) that appears to be universally distributed in frequency as D loc (ω) = A 4 ω 4 [13][14][15][16], with A 4 decreasing as the stability of the material increases [17].…”

Section: Introductionmentioning

confidence: 99%

Quasi-localized vibrational modes, boson peak and sound attenuation in model mass-spring networks

Mahajan,

Pica Ciamarra

2023

SciPost Phys.

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We introduce an algorithm that constructs disordered mass-spring networks whose elastic properties mimic that of glasses by tuning the fluctuations of the local elastic properties, keeping fixed connectivity and controlling the prestress. In two dimensions, the algorithm reproduces the dependence of glasses’ vibrational properties, such as quasi-localised vibrational modes and Boson peak, on the degree of stability. The sound attenuation displays Rayleigh scattering and disorder-broadening regimes at different frequencies, and the attenuation rate decreases with increased stability. Our results establish a strong connection between the vibrational features of disordered solids and the fluctuations of the local elastic properties and provide a new approach to investigating glasses’ vibrational anomalies.

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“…with θðxÞ the Heaviside step function, n weakly system dependent if not constant, and A D fixed by the normalization constraint. The characteristic QLMs size determines the boson peak, which is therefore not related to the first van Hove singularity of transverse waves [60]. The defect picture does not rely on the introduction of defects of a specific size but rather on the existence of a characteristic size, ξ d .…”

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confidence: 99%

Unifying Description of the Vibrational Anomalies of Amorphous Materials

Mahajan

Ciamarra

2021

Phys. Rev. Lett.

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The vibrational density of states DðωÞ of solids controls their thermal and transport properties. In crystals, the low-frequency modes are extended phonons distributed in frequency according to Debye's law, DðωÞ ∝ ω 2 . In amorphous solids, phonons are damped, and at low frequency DðωÞ comprises extended modes in excess over Debye's prediction, leading to the so-called boson peak in DðωÞ=ω 2 at ω bp , and quasilocalized ones. Here we show that boson peak and phonon attenuation in the Rayleigh scattering regime are related, as suggested by correlated fluctuating elasticity theory, and that amorphous materials can be described as homogeneous isotropic elastic media punctuated by quasilocalized modes acting as elastic heterogeneities. Our numerical results resolve the conflict between theoretical approaches attributing amorphous solids' vibrational anomalies to elastic disorder and localized defects.

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Disorder-induced vibrational anomalies from crystalline to amorphous solids

Cited by 5 publications

References 60 publications

Phonon behavior in a random solid solution: a lattice dynamics study on the high-entropy alloy FeCoCrMnNi

Phonon behavior in a random solid solution: a lattice dynamics study on the high-entropy alloy FeCoCrMnNi

Quasi-localized vibrational modes, boson peak and sound attenuation in model mass-spring networks

Unifying Description of the Vibrational Anomalies of Amorphous Materials

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