Observation of Two-Dimensional Phase Separation inHe3-He4Films

Abstract

New measurements of heat capacity for ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ adsorbed on ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ films are presented. It is found that for the thinnest ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ film used, and starting at a ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ coverage of 0.058 layer, 3.7 × ${10}^{-4\mathrm{}}$ ${\mathrm{\AA }}^{-2\mathrm{}}$, the data show a very sudden onset of degeneracy. It is found that these data are consistent with phase separation in the two-dimensional layer of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ at the surface of the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ film.