Hard domain walls in superfluid 3He-B

TL;DR

This paper theoretically investigates the structure, stability, and textures of domain walls between superfluid 3He-B phases, revealing a unique stable structure and its implications for half-quantum circulation.

Contribution

It provides a detailed Ginzburg-Landau analysis of B-B domain walls, identifying the only stable structure and exploring their effects on spin-orbit textures and circulation.

Findings

Only one domain wall structure is stable against perturbations.

B-B interfaces can induce textures similar to external walls.

Stable B-B interfaces can lead to half-quantum circulation.

Abstract

We study theoretically planar interfaces between two domains of superfluid 3He-B. The structure of the B-B walls is determined on the scale of the superfluid condensation energy, and thus the domain walls have thickness on the order of the Ginzburg-Landau coherence length. We study the stability and decay schemes of five inequivalent structures of such domain walls using one-dimensional Ginzburg-Landau simulation. We find that only one of the structures is stable against small perturbations. We also argue that B-B interfaces could result from adiabatic A to B transition and study textures at B-B interfaces. The B-B interface has a strong orienting effect on spin-orbit rotation producing textures similar as caused by external walls. We study the B-B interface in a parallel-plate geometry and find that the conservation of spin current sets an essential condition on the structure. The stable B-B interface gives rise to half-quantum circulation.