Phase diagram of 4He adsorbed in 1D 2.4 nm nanopores of FSM

Abstract

In systematic studies of superfluid 4He adsorbed in nanochannels with various diameters, qualitative differences appear in narrow channels below about 2.2-2.8 nm, which is likely to relate with the one-dimensional properties of 4He superfluid in nanochannels. In order to determine how 4He are adsorbed in 2.4 nm channels on the boundary, we have measured the heat capacities down to 0.15 K and determined the phase diagram. Crossover from normal fluid to localized state is observed up to 20 μmol/m2, larger than 18 μmol/m2 where the first adsorption layer is completed. And the quantum Bose fluid film is observed above 25 μmol/m 2. The superfluid region observed by a torsional oscillator appears to be inside of this Bose fluid region. © Published under licence by IOP Publishing Ltd.