Surface Confinement of Dysprosocenium Based Molecular Magnets on MgO(100) Surface: Insights from First-Principle Calculations

Abstract Preserving molecular magnetic properties upon surface deposition is crucial for molecular spintronics and quantum technologies. Herein, we studied the physisorption of two top-performing [(CpiPr5)Dy(Cp*)]+ (1) and [Dy(Cpttt)2]+ (2) single-ion magnets (SIMs) on the MgO(100) surface using periodic density functional theory (pDFT), ab initio molecular dynamics (AIMD) simulations to assess the effect of adsorption on their structural and magnetic properties post-deposition. DFT and AIMD simulations predict that parallel orientations are thermodynamically favorable; however, several surface adsorption sites are accessible with the same orientation at 300 K. Magnetic anisotropy analysis predicts stabilization of the mJ |±15/2⟩ ground state, with a barrier height (Ucal) ranging from 1300 to 1450 cm–1, similar to that of the pristine molecule, suggesting the geometries of 1 and 2 are intact upon deposition. CASSCF calculations on walker structures obtained from the AIMD snapshot show that thermal fluctuations marginally change the Ucal values. The calculated effective demagnetization barriers Ueff closely reproduce the computed Ucal values, while the predicted quantum tunneling of magnetization rate (τQTMZee) are remarkably long, ranging from 2.2 × 104 to 2.99 × 104 s, indicating strongly suppressed quantum tunneling and excellent magnetic performance of the surface-supported molecules. Our comprehensive analysis predicts MgO(100) as a robust platform for anchoring SIMs toward future quantum technologies.