# Boson peak in glasses


## theory

- 2008 [Universal link between the boson peak and transverse phonons in glass](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5457/nmat2293.pdf)

> We discovered evidence suggestive of the equality of the boson
> peak frequency to the Ioffe–Regel limit for ‘transverse’ phonons, above which transverse phonons no longer propagate. Our results
> indicate a possibility that the origin of the boson peak is transverse vibrational modes associated with defective soft structures in
> the disordered state. Furthermore, we suggest a possible link between slow structural relaxation and fast boson peak dynamics in
> glass-forming systems.


⏎⏎- Turlakov 2003 [Universal sound absorption in low-temperature glasses](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/4465/Low-temperature%2Bglasses%2BTurlakov%2B2003.pdf)

> Phenomenologically assuming a sharp decrease of shear relaxation time for large wavevector k > kξ
> density modes (where kξ is of order of inverse of several interatomic distances a), I develop a general
> elasto-hydrodynamic theory describing the low-energy excitations of glassy and amorphous solids


- [Heterogeneous Elasticity: The tale of the boson peak](https://arxiv.org/abs/2009.05970)
Walter Schirmacher, Giancarlo Ruocco

[Heterogeneous shear elasticity of glasses: the origin of the boson peak](https://www.nature.com/articles/srep01407.pdf?origin=ppub)

> ... in the boson peak region are produced by spatial fluctuations of dilatation-free shear stresses




- van Hove 

2011 [Equivalence of the Boson Peak in Glasses to the Transverse Acoustic van Hove Singularity in Crystals](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5456/physrevlett.106.225501.pdf)
A. I. Chumakov

2011 Reiner Zorn [Experiments suggest that the celebrated “boson peak”—a low-frequency vibrational feature characteristic of amorphous materials—may be related to a well-known phonon singularity in ordered crystalline materials.](https://physics.aps.org/articles/v4/44)


- 2017 [Universal structural softening in metallic glasses indicated by boson heat capacity peak](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5473/softening.pdf) M. Q. Jiang,

>  A main finding of the present study is that the boson heat capacity peaks involving both phonic and electronic contributions show an inversely linear correlation between their heights and position temperatures
 
> ... can be understood in terms of transverse soft modes associated with local soft regions

> We further suggest a possibility that the linear evolution of the **fast boson peaks can probe into the slow structural softening across the glass transition**, and the two dynamic processes are controlled by the short-time shear modulus associated with local soft regions in fragile glasses


## Baggioli 2019 [Vibrational density of states and specific heat in glasses from random matrix theory](https://arxiv.org/pdf/1903.05237.pdf)

> > The model is also able to reproduce, for the first time, the experimentally **observed inverse proportionality between the boson peak in the specific heat and the shear modulus**

> The linear in T regime is controlled by the low-frequency side of the random matrix spectrum, which goes as D(ω) = Aω + B, stemming
> directly from the Marchenko-Pastur scaling in the low eigenvalue regime,

> This result shows that at very low T the specific heat of the random spring network is linear in T, and that this
> behaviour is controlled by random matrix statistics and its interplay with the Goldstone phonons.


- linear-T specific heat

2019 [From random matrix theory to linear-in-T specific heat in glasses](https://arxiv.org/abs/1903.05237) Matteo Baggioli, Rico Milkus, Alessio Zaccone
> The model is also able to reproduce, for the first time, the experimentally
> observed inverse proportionality between the boson peak in the specific heat and the shear modulus

2020 [A new paradigm for the low-T glassy-like thermal properties of solids](https://arxiv.org/pdf/2008.01407.pdf)

> **New experimental and theoretical observations have questioned the origin of the boson peak and the linear in T specific heat exclusively from disorder and TLS.**

>  Using the formal analogy between phason modes (e.g. in quasicrystals and incommensurate lattices) and
> diffusons, and between amplitude modes and optical phonons, we suggest the existence of a more
> universal physics behind these properties. 


- anharmonism and damping


[Universal Origin of Boson Peak Vibrational Anomalies in Ordered Crystals and in Amorphous Materials](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5455/PhysRevLett.122.145501.pdf) 2019 Matteo Baggioli

[Shvaika, Schirmacher, Rucco - Absence of a boson peak in anharmonic phonon models with Akhiezer-type damping](https://arxiv.org/pdf/2104.13076.pdf)
[Reply to Shvaika et al.: Presence of a boson peak in anharmonic phonon models with Akhiezer-type damping](https://arxiv.org/pdf/2104.14428.pdf)

2009 [Connection between Boson Peak and Elastic Properties in Silicate Glasses](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5454/physrevlett.102.195502.pdf)


- universal?

[Unified theory of vibrational spectra in hard amorphous materials](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5562/PhysRevResearch.2.013267.pdf) 2020

# Parents

* Spectroscopy of condensed matter
* Universal properties of glasses - BOOKs
* Medium-range order in glasses and beyond
* Universal properties of glasses (at glass transition and low temperatures below 1K)
* Spectroscopy of condensed matter⏎
# Attachments

* [](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5454/physrevlett.102.195502.pdf)
* [](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5455/PhysRevLett.122.145501.pdf)
* [](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5456/physrevlett.106.225501.pdf)
* [](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5457/nmat2293.pdf)
* [](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5473/softening.pdf)
* [](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/5562/PhysRevResearch.2.013267.pdf)