Metal-organic frameworks (MOFs), which are self-assemblies of metal ions and organic ligands, provide a tunable platform to search a new state of matter. A two-dimensional (2D) perfect kagome lattice, whose geometrical frustration is a key to realizing quantum spin liquids, has been formed in the π - conjugated 2D MOF [Cu(CS)] (Cu-BHT). The recent discovery of its superconductivity with a critical temperature of 0.25 kelvin raises fundamental questions about the nature of electron pairing. Here, we show that Cu-BHT is a strongly correlated unconventional superconductor with extremely low superfluid density. A nonexponential temperature dependence of superfluid density is observed, indicating the possible presence of superconducting gap nodes. The magnitude of superfluid density is much smaller than those in conventional superconductors and follows the Uemura's relation of strongly correlated superconductors. These results imply that the unconventional superconductivity in Cu-BHT originates from electron correlations related to spin fluctuations of kagome lattice.
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http://dx.doi.org/10.1126/sciadv.abf3996 | DOI Listing |
Chemistry
January 2025
Indian Institute of Science Education and Research (IISER), Chemistry, Dr. Homi Bhabha Road, Pashan, 411008, Pune, INDIA.
Metal-organic frameworks (MOFs) are a fascinating class of structured materials with diverse functionality originating from the distinctive physicochemical properties. This review focuses on the specific chemical design of geometrically frustrated MOFs along with the origin of the intriguing magnetic properties. We have discussed the arrangement of spin centres (metal and ligand) which are responsible for the unusual magnetic phenomena in MOFs.
View Article and Find Full Text PDFAdv Mater
January 2025
Department of Physics, Pohang University of Science and Technology, 77, Cheongam-ro, Nam-gu, Pohang, 37673, Korea (the Republic of).
Janus materials, a novel class of materials with two faces of different chemical compositions and electronic polarities, offer significant potential for various applications with catalytic reactions, chemical sensing, and optical or electronic responses. A key aspect for such functionalities is face-dependent electronic bipolarity, which is usually limited by the chemical distinction of terminated surfaces and has not been exploited in the semiconducting regime. Here, it is showed that a Janus and Kagome van der Waals (vdW) material NbTeI has ferroelectric-like coherent stacking of the Janus layers and hosts strong electronic bipolar states in the semiconducting regime.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Department of Chemistry, The University of Hong Kong, Hong Kong, 999077, China.
Electrically conductive coordination polymers (ECCPs), particularly those incorporating benzenehexathiol (BHT) ligands, are emerging as a distinctive class of electronic materials with tunable semiconducting and metallic properties. However, the exploration of novel ECCPs with low-symmetry structures and electrical anisotropy remains under development. Here, we report the on-water surface synthesis of a novel ECCP, namely CuBHT, which exhibits a low-symmetry structure and unique in-plane electrical anisotropy that differs from the well-known CuBHT phase.
View Article and Find Full Text PDFNano Lett
January 2025
State Key Laboratory of Structural Analysis for Industrial Equipment & School of Physics, Dalian University of Technology, Dalian 116024 People's Republic of China.
Nanotechnology
January 2025
Departamento de Física, Universidade Federal do Ceará, Campus do Pici, 60455-900 Fortaleza, Ceará, Brazil.
We investigate the electronic properties of nanoribbons made out of monolayer Lieb, transition, and kagome lattices using the tight-binding model with a generic Hamiltonian. It allows us to map the evolutionary stages of the interconvertibility process between Lieb and kagome nanoribbons by means of only one control parameter. Results for the energy spectra, the density of states, and spatial probability density distributions are discussed for nanoribbons with three types of edges: straight, bearded, and asymmetric.
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