From Trivial Kondo Insulator Ce_{3}Pt_{3}Bi_{4} to Topological Nodal-Line Semimetal Ce_{3}Pd_{3}Bi_{4}.

Using the density functional theory combined with dynamical mean-field theory, we have performed systematic study of the electronic structure and its band topology properties of Ce_{3}Pt_{3}Bi_{4} and Ce_{3}Pd_{3}Bi_{4}. At high temperatures (∼290  K), the electronic structures of both compounds resemble the open-core 4f density functional calculation results. For Ce_{3}Pt_{3}Bi_{4}, clear hybridization gap can be observed below 72 K, and its coherent momentum-resolved spectral function below 18 K exhibits an topologically trivial indirect gap of ∼6  meV and resembles density functional band structure with itinerant 4f state. For Ce_{3}Pd_{3}Bi_{4}, no clear hybridization gap can be observed down to 4 K, and its momentum-resolved spectral function resembles electron-doped open-core 4f density functional calculations. The band nodal points of Ce_{3}Pd_{3}Bi_{4} at 4 K are protected by the gliding-mirror symmetry and form ringlike structure. Therefore, the Ce_{3}Pt_{3}Bi_{4} compound is topologically trivial Kondo insulator while the Ce_{3}Pd_{3}Bi_{4} compound is topological nodal-line semimetal.