Two-dimensional Fermi liquid in the highly correlated regime: The second layer ofHe3adsorbed on graphite

We present results on the magnetic susceptibility of the second atomic layer fluid of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ adsorbed on graphite over a large temperature and coverage range. The fluid is found to display the well characterized behavior of a Fermi liquid. The temperature dependence of the magnetic susceptibility can be described well by Dyugaev’s phenomenological theory of Fermi liquids. The effective Fermi temperature has been determined as a function of coverage. We find that the susceptibility enhancement factor (with respect to the Fermi gas of the same density) reaches values larger than in bulk liquid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ in high-areal-density fluids. In this regime the films constitute experimental model systems for the theory of strongly correlated fermions. Using previous heat-capacity measurements performed on the same system allows a direct comparison with the predictions of the quasilocalized model and the paramagnon model. © 1996 The American Physical Society.