Enhancement of ferromagnetism byp-wave Cooper pairing in superconducting ferromagnets

Abstract

In superconducting ferromagnets for which the Curie temperature T m exceeds the superconducting transition temperature T c , it was suggested that ferromagnetic spin fluctuations could lead to superconductivity with p-wave spin-triplet Cooper pairing. Using the Stoner model of itinerant ferromagnetism, we study the feedback effect of the p-wave superconductivity on the ferromagnetism. Below T c , the ferromagnetism is enhanced by the p-wave superconductivity. At zero temperature, the critical exchange interaction value for itinerant ferromagnetism is reduced by the strength of the p-wave pairing potential, and the magnetization increases correspondingly. More important, our results suggest that once the ferromagnetism is established, T m is unlikely to ever be below T c . For strong and weak ferromagnetism, three and two peaks in the temperature dependence of the specific heat are, respectively, predicted, the upper peak in the latter case corresponding to a first-order transition.

Superconductivity in a two-dimensional superconductor with Rashba and Dresselhaus spin–orbit couplings

“…2(b). The role of SOC in quasiparticle pairings analogous to that of the ferromagnetism in ferromagnetic superconductors [25]. When Rashba and Dresselhaus SOCs are mixed (θ = π/6, π/4), ∆ + is reduced with the increase of Dresselhaus component, while ∆ − is strengthened.…”

“…In the strong SOC limit [6,7], k B T C ≪ γ < µ, the theory of NCS superconductor is analogous to that of ferromagnetic superconductors [25], and then only intraband pairing is allowed to occur in the same quasiparticle band [5][6][7]. Consequently, a p-wave pairing is considered to be occur in each quasiparticle band, and the pairing Hamiltonian can be written as…”

Parity violation effects in the Josephson junction of a p -wave superconductor

“…30 , the relation ǫ = ǫ 0 holds. However, for anisotropic materials, during the change of the summation over k to three dimensional integration, the angular integrals in spherical coordinates remain the same, however, the radial variables are changed:…”

“…30 , described there for the case of an isotropic material. We extended this formalism for anisotropic materials.…”

“…30 , the Matsubara Green's functions 31 for this Hamiltonian are constructed, and, after summation over Matsubara frequencies, the equations are obtained for the magnetization, number of particles and gap parameters. By replacing all summations by continuum integrals in dimensionless energy units, rescaled by the factor 2 2m * , one receives the equations…”