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Onset of Superfluidity in ^{3}He Films
Masamichi Saitoh1, Hiroki Ikegami1, Kimitoshi Kono1
1The Center for Emergent Matter Science, RIKEN, Wako, Saitama 351-0198, Japan.
Physical Review Letters
|November 26, 2016
Summary
We studied superfluidity in helium-3 (³He) films, finding that the superfluid onset temperature decreases as film thickness shrinks. This temperature is significantly suppressed near the coherence length.
Area of Science:
- Low-temperature physics
- Condensed matter physics
Background:
- Superfluidity in helium-3 (³He) is a key phenomenon in quantum fluids.
- Understanding superfluid properties in thin films is crucial for condensed matter physics.
Purpose of the Study:
- To investigate the onset temperature of superfluidity in ³He films across a wide range of thicknesses.
- To compare experimental results with quasiclassical theory predictions.
Main Methods:
- Utilized microfabricated devices to precisely tune film thickness (d) from 0.06 to 10 μm.
- Measured the onset temperature of superfluidity (Tcf) as a function of film thickness.
Main Results:
- Observed a suppression of Tcf as film thickness (d) decreased, deviating from bulk ³He transition temperature.
- Tcf was strongly suppressed when d approached the coherence length of ³He (approximately 77 nm).
- Experimental Tcf as a function of d showed deviations from quasiclassical theory predictions for film thicknesses between 0.5 μm and 5 μm.
Conclusions:
- The study provides the first comprehensive behavior of ³He film superfluidity onset temperature.
- Observed deviations suggest limitations of current quasiclassical theory in certain film thickness regimes.
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