DFT Study of Bowtie Shaped Nanographene

The density functional theory (DFT) is used to analyze the fundamental electronic properties, electronic states of bowtie shaped nanographene (C38H18 Clar's Goblet, CG), which is expected to be applied to such as spintronic devices. We also analyze triangulene, which is similar to CG and easier to make larger structures by increasing connections than CG. We investigate up to the trimer for CG and up to the tetramer for triangulene. In addition, we calculate the electronic structure of nanographene doped with boron and nitrogen. CG and triangulene have smaller bandgaps with BN dopants at the ferromagnetic state. We find that in ferromagnetic states, nitrogen and boron doping brings the up-spin and down-spin levels closer to the Fermi level, especially in triangulene, both levels are almost equal to the Fermi level, and the wavefunctions are localized at both ends of the triangulene.