We have developed a method to probe the temperature of surface state electrons (SSE) above a superfluid Helium-4 surface using the Seebeck effect. In contrast to previously used SSE thermometry, this technique does not require detailed knowledge of the non-linear mobility. We demonstrate the use of this method by measuring energy relaxation of SSE at 1.6 K in a microchannel device with 0.6μ\mboxm deep helium. In this regime, both vapor atom scattering and 2-ripplon scattering contribute to energy relaxation to which we compare our measurements. We conclude that this technique provides a reliable measure of electron temperature while requiring a less detailed understanding of the electron interactions with the environment than previously utilized thermometry techniques.
@article{arxiv.1807.09166,
title = {Thermopower-based hot electron thermometry of helium surface states at 1.6 K},
author = {Ethan I. Kleinbaum and Stephen A. Lyon},
journal= {arXiv preprint arXiv:1807.09166},
year = {2018}
}