Spin-triplet superconducting pairing due to local Hund's rule and Dirac exchange - art. no. 104513

We discuss general implications of the local spin-triplet pairing among fer mions induced by local ferromagnetic exchange, an example of which is the H und's rule coupling. The quasiparticle energy and their wave function are d etermined for the three principal phases with the gap, which is momentum in dependent. We utilize the Bogolyubov-Nambu-de Gennes approach, which in the case of triplet pairing in the two-band case leads to the four-components wave function. Both gapless modes and those with an isotropic gap appear in the quasiparticle spectrum. A striking analogy with the Dirac equation is briefly explored. This type of pairing is relevant to relativistic fermions as well, since it reflects the fundamental discrete symmetry-particle inte rchange. A comparison with the local interband spin-singlet pairing is also made.