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arXiv · 1909.09258

Why phonon scattering in glasses is universally small at low temperatures

Herve M. Carruzzo·Clare C. Yu
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Abstract

We present a novel view of the standard model of tunneling two level systems (TLS) to explain the puzzling universal value of a quantity, $C\sim 3\times 10^{-4}$, that characterizes phonon scattering in glasses below 1 K as reflected in thermal conductivity, ultrasonic attenuation, internal friction, and the change in sound velocity. Physical considerations lead to a broad distribution of phonon-TLS couplings that (1) exponentially renormalize tunneling matrix elements, and (2) reduce the TLS density of states through TLS-TLS interactions. We find good agreement between theory and experiment for a variety of individual glasses.

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Herve M. Carruzzo, Clare C. Yu. 2019-09-19. Why phonon scattering in glasses is universally small at low temperatures. https://doi.org/10.1103/physrevlett.124.075902

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