Influence of exchange scattering on superfluid 3He states in nematic aerogel
The superfluid state in bulk liquid 3He is realized in the form of A or B phases. Uniaxially anisotropic aerogel (nafen) stabilizes the transition from the normal to the polar superfluid state which on further cooling transitions to the axipolar orbital glass state [Dmitriev, Senin, Soldatov, and Yudin, Phys. Rev. Lett. 115, 165304 (2015), 10.1103/PhysRevLett.115.165304]. This is the case in nafen aerogel preplated by several atomic layers of 4He. When pure liquid 3He fills the same nafen aerogel a solid-like layer of 3He atoms coats the aerogel structure. The polar state is not formed anymore and a phase transition occurs directly to the axipolar phase [Dmitriev, Soldatov, and Yudin, Phys. Rev. Lett. 120, 075301 (2018), 10.1103/PhysRevLett.120.075301]. The substitution of 4He by 3He atoms at the aerogel surface changes the potential and adds the exchange scattering of quasiparticles on the aerogel strands. A calculation shows that both of these effects can decrease the degree of anisotropy of scattering and suppress the polar phase formation. The derived anisotropy of the spin diffusion coefficient in globally anisotropic aerogel is determined by the same parameter which controls the polar state emergence, which allows one to check the effect of anisotropy change for different types of covering.
Physical Review B
- Pub Date:
- July 2018
- Condensed Matter - Other Condensed Matter
- 6 pages, no figures