An umbrella for electron rain: Dependence of magnetization on the direction of alkane bridge*

A promising class of molecular magnets emerges from triangular metal-center configurations since most of the structures exhibit an antiferromagnetically ordered ground state and consequent formation of a permanent electric dipole. This raises the possibility for switching between magnetic levels by an external electric field. An example is the Fe₃ qubit with low-energy states composed of both S=1/2 and S=5/2 local spins predicted by theory and experiment respectively[1,2].Here, we present calculated results based on density functional theory for switching the magnetism of the Fe₃-graphene system by controlling the orientation of a mechanical charge-transfer bridge,CH₄ .The total energy and therefore the electronic levels are strongly modified by the orientation of CH₄. The analysis of charge transfer and magnetic moment on the Fe atoms as well as on the graphene sheets along with the results of exchange coupling, shows clear evidence that the magnetism can be controlled by flipping the bridging methane and therefore provides a new route to electronically controlling the Fe₃ magnetic properties for quantum tasks. [1] Boudalis, A. K. et al.; Chem. Eur. J. 24, 14896–14900 (2018). [2] Johnson, A. I. et al.; J. Chem. Phys. 151, 174105 (2019).