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arXiv · 1810.01901

Orbital-Flop Transition of Angular Momentum in a Topological Superfluid

A. M. Zimmerman·J. I. A. Li·M. D. Nguyen·W. P. Halperin
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Abstract

The direction of the orbital angular momentum of the $B$-phase of superfluid $^3$He can be controlled by engineering the anisotropy of the silica aerogel framework within which it is imbibed. In this work, we report our discovery of an unusual and abrupt `orbital-flop' transition of the superfluid angular momentum between orientations perpendicular and parallel to the anisotropy axis. The transition has no hysteresis, warming or cooling, as expected for a continuous thermodynamic transition, and is not the result of a competition between strain and magnetic field. This demonstrates the spontaneous reorientation of the order parameter of an unconventional BCS condensate.

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A. M. Zimmerman, J. I. A. Li, M. D. Nguyen, W. P. Halperin. 2018-10-03. Orbital-Flop Transition of Angular Momentum in a Topological Superfluid. https://doi.org/10.1103/physrevlett.121.255303

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