Node-line Dirac semimetal manipulated via Kondo mechanism in nonsymmorphic CePt2Si2

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 noninteracting 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 ${\mathrm{CePt}}₂{\mathrm{Si}}₂$, and the feature of DNLs can be significantly manipulated by Kondo behavior in different temperature regions. Based on the density functional theory combining with dynamical mean-field theory $(\mathrm{DFT}+\mathrm{DMFT})$, we predict a transition to Kondo-coherent state at coherent temperature ${T}_{\mathrm{coh}}\ensuremath{\approx}80$ K upon cooling, verified by temperature dependence of $\mathrm{Ce}\text{\ensuremath{-}}4f$ self-energy, Kondo resonance peak, magnetic susceptibility, and momentum-resolved spectral function. Below ${T}_{\mathrm{coh}}$, 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 ${T}_{\mathrm{KS}}\ensuremath{\approx}600$ K, the destruction of local Kondo screening drives noninteracting 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.