Abstract
The influence of confinement on the phases of superfluid helium-3 is studied using the torsional pendulum method. We focus on the transition between the A and B phases, where the A phase is stabilized by confinement and a spatially modulated stripe phase is predicted at the A-B phase boundary. Here we discuss results from superfluid helium-3 contained in a single 1.08-μm-thick nanofluidic cavity incorporated into a high-precision torsion pendulum, and map the phase diagram between 0.1 and 5.6 bar. We observe only small supercooling of the A phase, in comparison to bulk or when confined in aerogel, with evidence for a non-monotonic pressure dependence. This suggests that an intrinsic B-phase nucleation mechanism operates under confinement. Both the phase diagram and the relative superfluid fraction of the A and B phases, show that strong coupling is present at all pressures, with implications for the stability of the stripe phase.
| Original language | English |
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| Article number | 15963 |
| Journal | Nature Communications |
| Volume | 8 |
| DOIs | |
| Publication status | Published - 3 Jul 2017 |
| MoE publication type | A1 Journal article-refereed |
Funding
We acknowledge input from H. Tye, M. Perelstein, E. Mueller, J.A. Sauls, J.J. Wiman, Hao Wu and A.Casey. We also acknowledge the assistance of R. DeAlba with imaging of the silicon surface depicted in Supplementary Fig. 2. This work was supported at Cornell by the NSF under DMR-1202991 and in London by the EPSRC under EP/J022004/1, and the European Microkelvin Platform.