One-Dimensional 4He and 3He Quantum Fluids Realized in Nanopores
- Department of Physics, Nagoya University, Nagoya 464-8602 (Japan)
- Department of Applied Physics and Chemistry, University of Electro-Communiations, Chofu 182-8585 (Japan)
We have studied 4He and 3He adsorbed onto FSM-16, which has straight one-dimensional (1D) nanopores 18 or 28 Aa in diameter. Fluid film tubes are formed on the nanopore walls covered with about one atomic layer of inert (solid) helium. The low-temperature heat capacity of 4He fluid tubes is linear in temperature. This is due to 1D phonons, whose contribution becomes observable at temperatures below 1/10 of the energy-level separation between the ground state and the first excited state quantized in the azimuthal direction. The superfluidity of 4He adsorbed in the nanopores was studied by a torsional oscillator. When the nonopores are preplated with 4He layers, 3He adatoms at a low density show a large heat capacity characteristic of a fluid. At high temperatures, the heat capacity is as large as that of a Boltzmann gas. With decreasing temperature, the heat capacity shows a Schottky-like peak followed by an asymptotic, linear dependence on temperature. A model calculation for a dilute 3He gas in an adsorption potential of a nanopore suggests a dimensional crossover from two dimensional to 1D around the Schottky-like peak. The calculation also suggests a degenerate 1D state at sufficiently lower temperatures than the energy gap for the motion in the azimuthal direction.
- OSTI ID:
- 20884834
- Journal Information:
- AIP Conference Proceedings, Vol. 850, Issue 1; Conference: LT24: 24. international conference on low temperature physics, Orlando, FL (United States), 10-17 Aug 2005; Other Information: DOI: 10.1063/1.2354705; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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