A flat-band perspective on the boson peak in amorphous solids

Fuente: arXiv
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Auteurs principaux: Mahajan, Shivam, Huang, Long-Zhou, Jiang, Cunyuan, Wang, Yun-Jiang, Ciamarra, Massimo Pica, Zhang, Jie, Baggioli, Matteo
Format: Preprint
Publié: 2025
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_version_ 1866917397070348288
author Mahajan, Shivam
Huang, Long-Zhou
Jiang, Cunyuan
Wang, Yun-Jiang
Ciamarra, Massimo Pica
Zhang, Jie
Baggioli, Matteo
author_facet Mahajan, Shivam
Huang, Long-Zhou
Jiang, Cunyuan
Wang, Yun-Jiang
Ciamarra, Massimo Pica
Zhang, Jie
Baggioli, Matteo
contents The boson peak is a characteristic anomaly of amorphous solids broadly defined as a low-energy excess in the density of states and heat capacity compared to the textbook predictions of Debye theory. The origin of this anomaly has long been the subject of ongoing debate and remains a topic of active controversy. We propose that the boson peak may have a defining dynamical feature: the accumulation of vibrational spectral weight within a narrow frequency window that is only weakly dependent on wavevector. In this perspective, the boson peak reflects a flat or weakly dispersive band in the dynamical structure factor rather than a propagating excitation. We revisit both experimental and simulation data from the literature through this lens and conduct further simulations in 2D and 3D amorphous systems. Taken together, these analyses provide compelling converging evidence for this interpretation and sharply constrain the space of viable theoretical descriptions of the boson peak.
format Preprint
id arxiv_https___arxiv_org_abs_2509_06340
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A flat-band perspective on the boson peak in amorphous solids
Mahajan, Shivam
Huang, Long-Zhou
Jiang, Cunyuan
Wang, Yun-Jiang
Ciamarra, Massimo Pica
Zhang, Jie
Baggioli, Matteo
Soft Condensed Matter
The boson peak is a characteristic anomaly of amorphous solids broadly defined as a low-energy excess in the density of states and heat capacity compared to the textbook predictions of Debye theory. The origin of this anomaly has long been the subject of ongoing debate and remains a topic of active controversy. We propose that the boson peak may have a defining dynamical feature: the accumulation of vibrational spectral weight within a narrow frequency window that is only weakly dependent on wavevector. In this perspective, the boson peak reflects a flat or weakly dispersive band in the dynamical structure factor rather than a propagating excitation. We revisit both experimental and simulation data from the literature through this lens and conduct further simulations in 2D and 3D amorphous systems. Taken together, these analyses provide compelling converging evidence for this interpretation and sharply constrain the space of viable theoretical descriptions of the boson peak.
title A flat-band perspective on the boson peak in amorphous solids
topic Soft Condensed Matter
url https://arxiv.org/abs/2509.06340