Theoretical investigation of decoherence channels in athermal phonon sensors

TL;DR

This paper uses first-principles calculations to analyze decoherence pathways of athermal phonons in semiconductors, providing insights into noise limitations and strategies for enhancing phonon sensor coherence.

Contribution

It offers a detailed theoretical investigation of phonon decay channels in Si and GaAs, highlighting the roles of anharmonic, isotopic, and interfacial scattering.

Findings

Quantified contributions of different scattering mechanisms.

Developed a model for thermal power estimation over time.

Discussed implications for noise and coherence in phonon sensors.

Abstract

The creation and evolution of nonequilibrium phonons is central in applications ranging from cosmological particle searches to decoherence processes in qubits. However, the fundamental understanding of decoherence pathways for athermal phonon distributions in solid-state systems remains an open question. Using first-principles calculations, we investigate the primary decay channels of athermal phonons in two technologically relevant semiconductors -- Si and GaAs. We quantify the contributions of anharmonic, isotopic, and interfacial scattering in these materials. From this, we construct a model to estimate the thermal power in a readout scheme as a function of time. We discuss the implication of our results on noise limitations in current phonon sensor designs and strategies for improving coherence in next-generation phonon sensors.