Accompanying data for "Chiral superfluid helium-3 in the quasi-two-dimensional limit"

This dataset includes the measured values of the superfluid transition temperature and the energy gap of the A phase of superfluid helium-3 confined in a 80 nm high slab-shaped cavity with specular quasiparticle scattering boundary conditions. Also corresponding calculations of the suppression of the superfluid transition temperature with almost fully specular boundaries are included. The preprint version of the manuscript detailing the findings of this study, and the used methods and techniques, is available in https://arxiv.org/abs/2409.12901.

Data from the experiments

'80nm_cavity_Tc_suppression_specular.dat' lists the measured superfluid transition temperatures in the confined cavity relative to the bulk-marker transition temperature corresponding to specular boundary condition and various pressures, i.e., various values of effective cavity height. These values are included in Figure 1 in the manuscript.

'80nm_cavity_A_phase_gap_specular_[pressure]bar.dat' files give the measured temperature dependence of the energy gap of superfluid A phase of helium-3 corresponding to specular boundary condition and various pressures. Values of the gap are based on the measured NMR frequency shift in the superfluid state as described in the manuscript. Four pressures are included in Figure 3 in the manuscript. All five pressures are shown in Supplementary Figure S3.

'80nm_cavity_initial_slopes_specular.dat' gives the measured initial slopes of the superfluid frequency shift versus temperature determined within different ranges below the measured superfluid transition temperature in the cavity for specular boundary conditions and various pressures. These values are needed in conversion between the frequency shift and the energy gap and are plotted in Figure 2(b) and Supplementary Figure S2 in the manuscript.

The values of superfluid transition temperature and the initial slopes measured using 192 nm high cavity are shown in couple of figures in the manuscript. Those values come from the earlier work, data of which can be found here: https://doi.org/10.17637/rh.12777620.v1

Calculations:

'calc_Tc_suppression_S[specularity].dat' show the calculated suppressed superfluid transition temperatures as a function of effective cavity height for two specularities close to being fully specular. The corresponding lines are shown in Figure 1(c) in the manuscript.

In all the calculations we have used the quasiclassical weak-coupling approach, as cited in the manuscript.

Literature values of bulk (or fully specular) superfluid transition temperature are given by D. S. Greywall in Phys. Rev. B 33, 7520 (1986) (https://doi.org/10.1103/PhysRevB.33.7520).

Values of the weak-coupling bulk energy gap of ³He-A can be found, for example, by using E. V. Thuneberg's calculator from http://ltl.tkk.fi/research/theory/qc/bcsgap.html.
The values as a function of temperature are also given in https://doi.org/10.17637/rh.12777620.v1.