Tuning the Ferroelectric Polarization in a Multiferroic Metal–Organic Framework

We perform density functional theory calculations on a recently synthesized metal–organic framework (MOF) with a perovskite-like topology ABX₃, i.e., [CH₃CH₂NH₃]­Mn­(HCOO)₃, and predict a multiferroic behavior, i.e., a coexistence of ferroelectricity and ferromagnetism. A peculiar canted ordering of the organic A-cation dipole moments gives rise to a ferroelectric polarization of ∼2 μC/cm². Starting from these findings, we show that by choosing different organic A cations, it is possible to tune the ferroelectric polarization and increase it up to 6 μC/cm². The possibility of changing the magnitude and/or the canting of the organic molecular dipole opens new routes toward engineering ferroelectric polarization in the new class of multiferroic metal–organic frameworks.