  Spin-triplet superconductivity is actively pursued in condensed matter
physics due to the potential applications in topological quantum computations.
The related pairing mechanism involving the interaction remains an important
research topic. Here we propose a universal approach to obtain p-wave triplet
superconductivity in the Hubbard models by simply changing the sign of the
hopping amplitudes of the spin-down electrons, and apply it to three prototype
two-dimensional lattices (honeycomb, square, and triangular). The parent
Hamiltonian at half filling has long-range magnetic order, which is
ferromagnetic in all three directions for the frustrated triangular lattices,
and ferromagnetic (antiferromagnetic) in the xy plane (z direction) for the
bipartite honeycomb and square lattices. The magnetic transitions occur at some
critical interactions on honeycomb and triangular lattices, which are estimated
by finite-size scalings. When the systems are doped, we find the triplet p-wave
pairing is a dominating superconducting instability. We demonstrate its
emergence is closely related to the strong ferromagnetic spin fluctuations
induced by the doping. Our results provide an understanding of the
microscopical triplet-pairing mechanism, and will be helpful in the search for
spin-triplet superconducting materials.
