Dirac-like fermions and node-loop features in bilayer BC3 sheet sandwiching a triangular alkaline metal layer

• The bilayer BC3 with a sodium insertion layer shows Dirac-like fermion feature.
• The new structure possesses a node-loop on the Fermi surface.
• It also has excellent thermodynamic and kinetic stability.

Using density-functional calculations we have investigated the features of massless relativistic Dirac-like fermion and node-loop in bilayer BC3 sheet sandwiching a triangular alkaline metal layer. Superposition of single-sheet spectra combined with the alkaline metal doping gives rise to the Dirac-like spectrum and an interesting node-loop on the Fermi surface, which is similar to that in AA-stacked bilayer graphene. Furthermore, the sandwich structures are thermodynamically and kinetically stable due to the presence of strong ionic bonding between alkaline metal layer and BC3 sheets. The newly predicted structures can be taken as good candidates to investigate Dirac-like particles and 2D Dirac semimetal features.