Fig. 5: Electronic properties of the Si2He compound.

Electronic band structures of a oP36-Si2He, b tP9-Si2He, c mC18-Si2He, and d mC12-Si2He at 0 GPa calculated based on the HSE06 functional. Red solid and blue hollow circles represent the valence band maximum and conduction band minimum, respectively. The lower panels in each figure are the square of the transition dipole moment89.