Energy of Stable Half-Quantum Vortex in Equal-Spin-Pairing

In the triplet equal-spin-pairing states of both 3He — A phase and Sr2RuO4 superconductor, existence of Half-Quantum Vortices (HQVs) are possible. The vortices carry half-integer multiples of magnetic quantum flux Φ0 = hc/2e. Our method is based on the explanation of the HQV in terms of a BCS—like wave function with a spin-dependent boots. To obtain equilibrium condition for such systems, one has to take into account not only weak interaction energy but also effects of Landau Fermi liquid. We have considered l = 2 order effects of the Landau Fermi liquid. We have shown that the effects of Landau Fermi liquid interaction with l = 2 are negligible. In stable HQV, an effective Zeeman field exists. In the thermodynamic stability state, the effective Zeeman field produces a non-zero spin polarization in addition to the polarization of external magnetic field.