Structural, Thermodynamic, and Transport Properties of the Small-Gap Two-Dimensional Metal-Organic Kagomé Materials Cu3(hexaiminobenzene)2and Ni3(hexaiminobenzene)2
Berry T, Morey JR, Arpino KE, Dou JH, Felser C, Dinca M, Mcqueen TM (2022)
Publication Type: Journal article
Publication year: 2022
Journal
Book Volume: 61
Pages Range: 6480-6487
Journal Issue: 17
DOI: 10.1021/acs.inorgchem.2c00081
Abstract
Metal-organic frameworks (MOFs) provide exceptional chemical tunability and have recently been demonstrated to exhibit electrical conductivity and related functional electronic properties. The kagomé lattice is a fruitful source of novel physical states of matter, including the quantum spin liquid (in insulators) and Dirac fermions (in metals). Small-bandgap kagomé materials have the potential to bridge quantum spin liquid states and exhibit phenomena such as superconductivity but remain exceptionally rare. Here we report a structural, thermodynamic, and transport study of the two-dimensional kagomé metal-organic frameworks Ni3(HIB)2 and Cu3(HIB)2 (HIB = hexaiminobenzene). Magnetization measurements yield Curie constants of 0.989 emu K (mol Ni)-1 Oe-1 and 0.371 emu K (mol Cu)-1 Oe-1, respectively, close to the values expected for ideal S = 1 Ni2+ and S = 1/2 Cu2+. Weiss temperatures of -10.6 and -14.3 K indicate net weak mean field antiferromagnetic interactions between ions. Electrical transport measurements reveal that both materials are semiconducting, with gaps (Eg) of 22.2 and 103 meV, respectively. Specific heat measurements reveal a large T-linear contribution γof 148(4) mJ mol-fu-1 K-2 in Ni3(HIB)2 with only a gradual upturn below ?5 K and no evidence of a phase transition to an ordered state down to 0.1 K. Cu3(HIB)2 also lacks evidence of a phase transition above 0.1 K, with a substantial, field-dependent, magnetic contribution below ?5 K. Despite them being superficially in agreement with the expectations of magnetic frustration and spin liquid physics, we ascribe these observations to the stacking faults found from a detailed analysis of synchrotron X-ray diffraction data. At the same time, our results demonstrate that these MOFs exhibit localized magnetism with simultaneous proximity to a metallic state, thus opening up opportunities to explore the connection between the insulating and metallic ground states of kagomé materials in a highly tunable chemical platform.
Involved external institutions
Johns Hopkins University (JHU)
United States (USA) (US)
Max-Planck-Institut für Chemische Physik fester Stoffe (MPI CPfS) / Max Planck Institute for Chemical Physics of Solids
Germany (DE)
Massachusetts Institute of Technology (MIT)
United States (USA) (US)
United States (USA) (US)
Max-Planck-Institut für Chemische Physik fester Stoffe (MPI CPfS) / Max Planck Institute for Chemical Physics of Solids
Germany (DE)
Massachusetts Institute of Technology (MIT)
United States (USA) (US)
How to cite
APA:
Berry, T., Morey, J.R., Arpino, K.E., Dou, J.-H., Felser, C., Dinca, M., & Mcqueen, T.M. (2022). Structural, Thermodynamic, and Transport Properties of the Small-Gap Two-Dimensional Metal-Organic Kagomé Materials Cu3(hexaiminobenzene)2and Ni3(hexaiminobenzene)2. Inorganic Chemistry, 61(17), 6480-6487. https://dx.doi.org/10.1021/acs.inorgchem.2c00081
MLA:
Berry, Tanya, et al. "Structural, Thermodynamic, and Transport Properties of the Small-Gap Two-Dimensional Metal-Organic Kagomé Materials Cu3(hexaiminobenzene)2and Ni3(hexaiminobenzene)2." Inorganic Chemistry 61.17 (2022): 6480-6487.
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