  We consider a two-component pancake-shaped, i.e., effectively two-dimensional
(2D), Bose-Einstein condensate (BEC) coupled by the spin-orbit (SO) and Rabi
terms. The SO coupling adopted here is of the mixed Rashba-Dresselhaus type.
For this configuration, we derive a system of two 2D nonpolynomial
Schr\"odinger equations (NPSEs), for both attractive and repulsive interatomic
interactions. In the low- and high-density limits, the system amounts to
previously known models, namely, the usual 2D Gross-Pitaevskii equation, or the
Schr\"odinger equation with the nonlinearity of power 7/3. We present simple
approximate localized solutions, obtained by treating the SO and Rabi terms as
perturbations. Localized solutions of the full NPSE system are obtained in a
numerical form. Remarkably, in the case of the attractive nonlinearity acting
in free space (i.e., without any 2D trapping potential), we find parameter
regions where the SO and Rabi couplings make 2D fundamental solitons
dynamically stable.
