Thermodynamic Evidence for Density Wave Order in Two Dimensional 4He Supersolid
Abstract
We previously reported the discovery of a two dimensional He supersolid; a state with intertwined density wave and superfluid order, observed in the second layer of He adsorbed on graphite. In this Letter we provide direct evidence for the density wave order, obtained by doping the layer with a small concentration of He atoms (impuritons). The heat capacity, magnetization and NMR relaxation times of the He were measured over a wide temperature range from 200 K to 500 mK. They provide evidence for changes in the ground state in the second layer film as the amount of He is increased at various fixed He doses. Clear evidence is obtained for a solid second layer film, matching the r\a'egime of superfluid response previously observed in pure He films.
Cite
@article{arxiv.2410.10302,
title = {Thermodynamic Evidence for Density Wave Order in Two Dimensional 4He Supersolid},
author = {J. Knapp and J. Nyeki and H. Patel and F Ziouzia and B. P. Cowan and J. Saunders},
journal= {arXiv preprint arXiv:2410.10302},
year = {2025}
}
Comments
Main body of the paper plus supplementary material