  Motivated by the fact that the Dirac phase in the PMNS matrix is the only
CP-violating parameter in the leptonic sector that can be measured in neutrino
oscillation experiments, we examine the possibility that it is the dominant
source of CP violation for leptogenesis caused by the out-of-equilibrium decays
of heavy singlet fermions. We do so within a low-scale extended type-I seesaw
model, featuring two Standard Model singlet fermions per family, in which
lepton number is approximately conserved such that the heavy singlet neutrinos
are pseudo-Dirac. We find that this produces a predictive model of
leptogenesis. Our results show that for low-scale thermal leptogenesis, a pure
inverse-seesaw scenario fails to produce the required asymmetry, even
accounting for resonance effects, because wash-out processes are too efficient.
Dirac-phase leptogenesis is, however, possible when the linear seesaw term is
switched on, with the aid of the resonance contributions naturally present in
the model. Degenerate and hierarchical spectra are considered -- both can
achieve Dirac-phase leptogenesis, although the latter is more constrained.
Finally, although unable to probe the parameter space of Dirac-phase
leptogenesis, the contributions to unitarity violation of the PMNS matrix,
collider constraints and charged-lepton flavour-violating processes are
calculated and we further estimate the impact of the future experiments MEG-II
and COMET for such models.
