Phonon-Mediated Anomalous Dynamics of Defects

TL;DR

This paper investigates how line defects in elastic media interact with phonons, revealing anomalous dynamics such as anisotropic mass, resonant dissipation, and potential shock wave formation at high frequencies.

Contribution

It introduces a detailed analysis of defect-phonon interactions, highlighting inertial coupling effects that cause unconventional defect dynamics and instabilities.

Findings

Anisotropic and anomalous mass and elastic constants for defect-lattice modes.

Resonant dissipation through phonon excitation.

Potential formation of shock waves at high-frequency defect oscillations.

Abstract

Dynamics of an array of line defects interacting with a background elastic medium is studied in the linear regime. It is shown that the inertial coupling between the defects and the ambient phonons leads to an anomalous response behavior for the deformation modes of a defect-lattice, in the form of anisotropic and anomalous mass and elastic constants, resonant dissipation through excitation of phonons, and instabilities. The case of a single fluctuating line defect is also studied, and it is shown that it could lead to formation of shock waves in the elastic medium for sufficiently high frequency deformation modes.