Abstract The presence of a non-centrosymmetric crystal structure and in-plane mirror symmetry allows
an Ising spin-orbit coupling to form in some two-dimensional materials. Examples include transition
metal dichalcogenide superconductors like monolayer NbSe2, MoS2, TaS2, and PbTe2, where a nontrivial nature of the superconducting state is currently being explored. In this study, we develop
a microscopic formalism for Ising superconductors that captures the superconducting instability
arising from a momentum-dependent spin- and charge-fluctuation-mediated pairing interaction.
We apply our pairing model to the electronic structure of monolayer NbSe2, where first-principles
calculations reveal the presence of strong paramagnetic fluctuations. Our calculations provide a
quantitative measure of the mixing between the even- and odd-parity superconducting states and
its variation with Coulomb interaction. Further, numerical analysis in the presence of an external
Zeeman field reveals the role of Ising spin-orbit coupling and mixing of odd-parity superconducting
state in influencing the low-temperature enhancement of the critical magnetic field.