  Dirac node lines (DNLs) are characterized by Dirac-type linear crossings
between valence and conduction bands along one-dimensional node lines in the
Brillouin zone (BZ). Spin-orbit coupling (SOC) usually shifts the degeneracy at
the crossings thus destroys DNLs, and so far the reported DNLs in a few
materials are non-interacting type, making the search for robust interacting
DNLs in real materials appealing. Here, via first-principle calculations, we
reveal that Kondo interaction together with nonsymmorphic lattice symmetries
can drive a robust interacting DNLs in a Kondo semimetal CePt_2Si_2, and the
feature of DNLs can be significantly manipulated by Kondo behavior in different
temperature regions. Based on the density function theory combining dynamical
mean-field theory (DFT+DMFT), we predict a transition to Kondo-coherent state
at coherent temperature T_coh= 80 K upon cooling, verified by temperature
dependence of Ce-4f self-energy, Kondo resonance peak, magnetic susceptibility
and momentum-resolved spectral. Below T_coh, well-resolved narrow heavy-fermion
bands emerge near the Fermi level, constructing clearly visualized interacting
DNLs locating at the BZ boundary, in which the Dirac fermions have strongly
enhanced effective mass and reduced velocity. In contrast, above a crossover
temperature T_KS =600 K, the destruction of local Kondo screening drives
non-interacting DNLs which are comprised by light conduction electrons at the
same location. These DNLs are protected by lattice nonsymmorphic symmetries
thus robust under intrinsic strong SOC. Our proposal of DNLs which can be
significantly manipulated according to Kondo behavior provides an unique
realization of interacting Dirac semimetals in real strongly correlated
materials, and serves as a convenient platform to investigate the effect of
electronic correlations on topological materials.
