Incipient Nodal Pairing in Planar $\mathit{d}$-wave Superconductors

The possibility of a second pairing transition $d\to d+is$ ( ${d+id}^{\prime }$) in planar $d$-wave superconductors which occurs in the absence of external magnetic field, magnetic impurities, or boundaries is established in the framework of the nonperturbative phenomenon of dynamical chiral symmetry breaking in the system of $(2+1)$-dimensional Dirac-like nodal quasiparticles. We determine the critical exponents and quasiparticle spectral functions that characterize the corresponding quantum-critical behavior and discuss some of its potentially observable spectral and transport features.