  It was recently shown that conventional phonon-electron interactions induce
triplet pairing states in time-reversal invariant 3D Dirac semi - metals
provided magnetic impurities or exchange interactions are strong enough?. The
order parameter in this case is a vector field. Starting from the microscopic
model of the isotropic Dirac semi-metal, the Ginzburg-Landau energy for this
field is derived using the Gor'kov technique. It was found that the transversal
coherence length is much smaller than the longitudinal despite the isotropy.
Several new features appear when an external field is applied. The Ginzburg -
Landau model is used to investigate magnetic properties of such
superconductors. Using the small deviation method the magnetic penetration
depth was found also to be vastly different for longitudinal and transverse
fluctuations. As a result the superconductor responds as type I to a transverse
perturbation, while with respect to a longitudinal perturbation it behaves as
type II. At large fields the order parameter orients itself perpendicular to
the field direction. The triplet superconductor persists at arbitrarily high
magnetic field (no upper critical magnetic field) like in some p wave
superconductors.
