  Based on combined density functional theory and nonequilibrium Greens
function quantum transport studies, we have demonstrated quantum interference
effects on the transverse conductance of Hachimoji synthetic nucleic acids
placed between the oxygen-terminated zigzag graphene nanoribbon nanoelectrodes.
We theorize that the QI effect could be well preserved in pi-pi coupling
between a nucleobase molecule and the carbon-based nanoelectrode. Our study
indicates that QI effects such as anti-resonance or Fano-resonance that affect
the variation of transverse conductance depending on the nucleobase
conformation. Further, a variation of up to 2-5 orders of magnitude is observed
in the conductance upon rotation for all the nucleobases. The current-voltage
characteristics results suggest a distinct variation in the electronic
tunnelling current across the proposed nanogap device for all the five
nucleobases with the applied bias voltage. The different rotation angles keep
the distinct feature of the nucleobases in both transverse conductance and
tunnelling current features. Both features could be utilized in an accurate
synthetic DNA sequencing device.
