Quasiparticle interactions in two-dimensional fluid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ films adsorbed on graphite

The nuclear magnetic susceptibility of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ adsorbed on the surface of graphite, plated with a monolayer of solid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, has been measured at surface densities less than 0.055 Å ${}_{}{}^{\mathrm{-}2}{}_{}{}^{}$ and at temperatures down to 6 mK. A temperature-independent susceptibility is observed at low temperatures, which is strongly enhanced over the ideal-gas value, due to quasiparticle interactions. The inferred Landau-Fermi-liquid parameters allow a comparison with microscopic theories of interacting Fermi systems.