In superfluid 3He-B confined in a slab geometry, domain walls between regions of different order parameter orientation are predicted to be energetically stable. Formation of the spatially-modulated superfluid stripe phase has been proposed. We confined 3He in a 1.1 μm high microfluidic cavity and cooled it into the B phase at low pressure, where the stripe phase is predicted. We measured the surface-induced order parameter distortion with NMR, sensitive to the formation of domains. The results rule out the stripe phase, but are consistent with 2D modulated superfluid order.
@article{arxiv.1805.02053,
title = {Evidence for a Spatially-Modulated Superfluid Phase of $^3$He under Confinement},
author = {Lev V. Levitin and Ben Yager and Laura Sumner and Brian Cowan and Andrew J. Casey and Nikolay Zhelev and Robert G. Bennett and Jeevak M. Parpia and John Saunders},
journal= {arXiv preprint arXiv:1805.02053},
year = {2021}
}