We develop a theory of ultrasound decay rate α in a model of a superconductor with a large pseudogap ΔP, and show that at low temperatures (T≪Tc) the magnitude of the decay rate α is controlled by the ratio of T/Δ, where Δ≪ΔP is a superconducting collective gap. Thus we propose new method to measure the collective gap Δ in a situation when strong pseudogap is present.
@article{arxiv.1609.01683,
title = {Ultrasonic attenuation in a pseudogapped superconductor},
author = {A. V. Shtyk and M. V. Feigel'man},
journal= {arXiv preprint arXiv:1609.01683},
year = {2017}
}