A new paradigm for the low-T glassy-like thermal properties of solids

Abstract

Glasses and disordered materials are known to display anomalous features in the density of states, in the specific heat and in thermal transport. Nevertheless, in recent years, the question whether these properties are really anomalous (and peculiar of disordered systems) or rather more universal than previously thought, has emerged. 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. The same properties have been indeed observed in ordered or minimally disordered compounds and in incommensurate structures for which the standard explanations are not applicable. 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. In particular, we strengthen the idea that linear in T specific heat is linked to low energy diffusive modes and that a BP excess can be simply induced by gapped optical-like modes.

arXiv commentv1: 5 pages, 4 figures

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Cited by in corpus (9)

• Degradation of phonons in disordered moiré superlattices
• Symmetry Origin of Lattice Vibration Modes in Twisted Multilayer Graphene: Phasons vs Moiré Phonons
• Universal non-Debye low-frequency vibrations in sheared amorphous solids
• Stringlet Excitation Model of the Boson Peak
• Extended linear-in-$T$ resistivity due to electron-phason scattering in moiré superlattices
• Glassy heat capacity from overdamped phasons and a hypothetical phason-induced superconductivity in incommensurate structures
• Atomistic mechanisms of dynamics in a two-dimensional dodecagonal quasicrystal
• Unusual effect of high pressures on phase transformations in Ni${}_{62}$Nb${}_{38}$ alloy
• Temperature crossovers in the specific heat of amorphous magnets