Much ado about MOFs: Metal-Organic-Frameworks as Quantum Materials

TL;DR

Metal-organic frameworks (MOFs) are presented as a highly tunable platform for quantum materials, capable of hosting entangled magnetism, superconductivity, and topology through modular chemistry. Magnetic MOFs (mMOFs) enable Hamiltonian engineering by tuning magnetic interactions, spin magnitudes, lattice geometries, dimensionality, and light-responsive behavior. The article reviews progress toward low-temperature magnetic states in MOFs, including kagome and other lattice motifs with reports of quantum spin liquids and related phenomena, while underscoring the need for improved single-crystal growth and spectroscopic probes. It discusses challenges such as sample fragility and hydrogen-rich content that complicates neutron scattering, and highlights opportunities in advanced synthesis (CVD, molecular epitaxy), defect engineering, and interdisciplinary collaboration, supported by community workshops and funding from the ARO.

Abstract

Metal-organic frameworks (MOFs) are a highly tunable class of crystalline materials where metal atoms or clusters are connected by organic linkers. They offer a versatile platform for exploring quantum phenomena such as entangled magnetism, superconductivity, and topology. Particularly for magnetism, their modular chemistry enables extensive control over magnetic interactions, spin magnitudes, lattice geometries, and even light-responsiveness, making them a uniquely adaptable platform. However, despite their promise, their low-temperature behavior and magnetic properties remain largely unexplored and represent an underappreciated opportunity in quantum materials research. With potential applications ranging from quantum computation to energy transfer, we believe that MOFs and particularly magnetic MOFs offer a vast and largely untapped frontier for transformative discoveries and high-impact quantum materials research.

Figures (1)

• Figure 1: (a) Schematic view of a magnetic metal-organic framework crystal structure: magnetic metal nodes (M) are connected into a crystal structure by organic linkers (blue and red bars). Linkers can be similar or different in- and out-of-plane. (b) An example of the crystal structure of MIL-47 containing V centers, where spin chains hosted by VO$_6$ octahedra are connected into crystollagraphic network by bdc (benzenedicarboxylic acid) molecules Barthelet2002. (c) Crystal structure of triangular lattice magnetic MOFs based on boron imidazolate frameworks (BIFs), Co- BIF and Ni-BIF. Triangular lattice Co-BIF shows antiferromagnetic interactions on the order of 1 K, and a spin-crossover-like effect in magnetic susceptibility due to thermal depopulation of excited crystal electric field levels. Magnetic properties of Ni-BIF suggest sizable ferromagnetic interactions davis2024tunable. All structures visualized in VESTA.