Mechanism and Application of Magnetic Anisotropy of a Single-Molecule Magnet Modulated by a Molecular Junction

The development of spintronic and quantum computing has inspired researchers to search for single-molecule magnets with stable structures that could be modulated repetitively. Modulation and utilization of the magnetic state of a single-molecule magnet is essential for quantum information manipulation. Moreover, in order to better design quantum information devices, it is important to explore the influence of the molecular structure on the spin center theoretically. In the present work, through density functional theory calculations, we systematically studied the spin–orbit coupling effect in the Cu–nickelocene–Cu magnetic molecular junction, and clarified the strain effect on the magnetic anisotropy energy (MAE) by developing the theoretical model based on spin–orbital coupling interaction. We quantitatively demonstrated that the tensile strain can lead to an abnormal increase of the MAE. Furthermore, it is found that the shift of the deep energy level and the change of the composition of d-orbitals in the hybrid molecular orbitals are the key factors to determine the strength of the spin–orbit coupling. This method will be widely applicable for the construction of similar magnetic molecular junction components.