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 ${\mathrm{Ce}}_{3}{\mathrm{Pt}}_{3}{\mathrm{Bi}}_{4}$ and ${\mathrm{Ce}}_{3}{\mathrm{Pd}}_{3}{\mathrm{Bi}}_{4}$. At high temperatures ($\ensuremath{\sim}290\text{ }\text{ }\mathrm{K}$), the electronic structures of both compounds resemble the open-core $4f$ density functional calculation results. For ${\mathrm{Ce}}_{3}{\mathrm{Pt}}_{3}{\mathrm{Bi}}_{4}$, 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 $\ensuremath{\sim}6\text{ }\text{ }\mathrm{meV}$ and resembles density functional band structure with itinerant $4f$ state. For ${\mathrm{Ce}}_{3}{\mathrm{Pd}}_{3}{\mathrm{Bi}}_{4}$, 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 ${\mathrm{Ce}}_{3}{\mathrm{Pd}}_{3}{\mathrm{Bi}}_{4}$ at 4 K are protected by the gliding-mirror symmetry and form ringlike structure. Therefore, the ${\mathrm{Ce}}_{3}{\mathrm{Pt}}_{3}{\mathrm{Bi}}_{4}$ compound is topologically trivial Kondo insulator while the ${\mathrm{Ce}}_{3}{\mathrm{Pd}}_{3}{\mathrm{Bi}}_{4}$ compound is topological nodal-line semimetal.