Ligand Optimization for the Spin-Lattice Coupling of Single-Molecule Magnets Mn₃

Single molecule magnets (SMM) exhibit a pseudo-multiferroicity which arises from structural changes that occur during spin state transitions. This spin-lattice coupling leads directly to magnetocapacitance which may also allow the spin state of the ground state to be tuned via strain. We propose that this tuning can be performed via replacement of the ligands which surround the SMM core atoms, and we attempt to search for a ligand which maximizes the spin-lattice coupling in the SMM Mn₃ as a test case. We use density functional theory (DFT) calculations, Bayesian optimization, and slightly modified atomic environment vectors (AEVs) to perform the search. These techniques are employed in order to minimize the cost of searching through a large number of candidate ligands from the PubChem database. Following this procedure, we have obtained evidence that the spin-lattice coupling can be affected through a judicious choice of ligand.