First-principles determination of magnetic properties of CoCp2 on the Cr(001) surface

Through density-functional calculations, we systematically studied the exchange bias effect of the antiferromagnetic Cr(001) substrate on a single magnetic molecule $\mathrm{Co}{\mathrm{Cp}}₂$. The magnetic moment and magnetic anisotropy of $\mathrm{Co}{\mathrm{Cp}}₂$ are largely tuned by the charge transfer between the molecule and substrate. A large exchange energy of \ensuremath{\sim}94 meV is found, which essentially pins the spin orientation of $\mathrm{Co}{\mathrm{Cp}}₂$. This makes $\mathrm{Co}{\mathrm{Cp}}₂/\mathrm{Cr}(001)$ an ideal combination for quantum sensing as its quantum spin states are well decoupled from those of the target magnetic entities. This work paves a way for the development of local quantum sensing with scanning probe techniques.