Possible one-dimensional ³He quantum fluid formed in nanopores

Heat capacity measurements have been made down to 5 mK for ³He fluid films adsorbed in one-dimensional (1D) nanometer-scale pores, 28 Å in diameter, preplated with ⁴He of 1.47 atomic layers. At low ³He density, the heat capacity shows a density-dependent, Schottky-like peak near 150 mK asymptoting to the value corresponding to a 2D Boltzmann gas at high temperatures. The peak behavior is attributed to the crossover from a 2D gas to a ID state at low temperatures. The degenerate state of the ID ³He fluid is indicated by a predominantly linear temperature dependence below about 30 mK.