The A-B transition in superfluid 3He under confinement in a thin slab geometry

N. Zhelev; T. S. Abhilash; E. N. Smith; R. G. Bennett; X. Rojas; L. V. Levitin; J. Saunders; J. M. Parpia

doi:10.1038/ncomms15963

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arXiv · 1610.07186

The A-B transition in superfluid 3He under confinement in a thin slab geometry

N. Zhelev·T. S. Abhilash·E. N. Smith·R. G. Bennett·X. Rojas·L. V. Levitin·J. Saunders·J. M. Parpia

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Abstract

The influence of confinement on the topological phases of superfluid 3He is studied using the torsional pendulum method. We focus on the phase transition between the chiral A-phase and the time-reversal-invariant B-phase, motivated by the prediction of a spatiallymodulated (stripe) phase at the A-B phase boundary. We confine superfluid 3He to a single 1.08 {\mu}m 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. This has a non-monotonic pressure dependence, suggesting that a new intrinsic B-phase nucleation mechanism operates under confinement, mediated by the putative stripe phase. 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.

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N. Zhelev, T. S. Abhilash, E. N. Smith, R. G. Bennett, X. Rojas, L. V. Levitin, J. Saunders, J. M. Parpia. 2016-10-23. The A-B transition in superfluid 3He under confinement in a thin slab geometry. https://doi.org/10.1038/ncomms15963

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