Triplet superconductivity in the repulsively interacting electron system on a triangular lattice: a possibility of magnetic-field-induced superconductivity

A disconnected Fermi surface as exemplified by dilute electrons in the triangular lattice has been theoretically shown by Kuroki and Arita to work favorably for spin-triplet pairing mediated by ferromagnetic fluctuations due to the electron-electron repulsion. Here we propose that a relatively small magnetic field can favor the realization of the triplet superconductivity, where the mechanism is anisotropic ferromagnetic fluctuations and the coupling of longitudinal spin fluctuations with the ferromagnetic spin wave. We have confirmed the idea with a quantum Monte-Carlo study in combination with the dynamical cluster approximation, where the magnetic field is shown to enhance the pairing in the ↑↑ channel.