Coherent spin manipulation in triangulene by a tip-induced electric field

We have proposed a scheme of coherent spin manipulation in a triangulene using the electric field generated by a scanning-tunneling-microscope (STM) tip. The study was inspired by successful synthesis of triangulenes and atomic-scale manipulation of STM tips. The electric-field evolutions of the energy spectra and the system's spin are obtained using both the Hartree-Fock (HF) model and the configuration-interaction (CI) model. The advantage of the CI model, compared with the HF model, is the ability to accurately describe the mixing of spin states, which is necessary for studying spin manipulation. The results show that the tip electric field can achieve both the spin depolarization and the mixing of spin states. Moreover, the energy splitting induced by the spin mixing can meet the requirement for the coherence of the spin manipulation. Our findings support the possibility of using the spin of a triangulene as a carbon-based qubit.