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1. Ultrahard magnetism from mixed-valence dilanthanide complexes with metal-metal bonding

   https://doi.org/10.1126/science.abl5470  

   Gould, Colin A.; McClain, K. Randall; Reta, Daniel; Kragskow, Jon G.; Marchiori, David A.; Lachman, Ella; Choi, Eun-Sang; Analytis, James G.; Britt, R. David; Chilton, Nicholas F.; et al (January 2022, Science)

   Metal-metal bonding interactions can engender outstanding magnetic properties in bulk materials and molecules, and examples abound for the transition metals. Extending this paradigm to the lanthanides, herein we report mixed-valence dilanthanide complexes (Cp iPr5 ) 2 Ln 2 I 3 (Ln is Gd, Tb, or Dy; Cp i Pr5 , pentaisopropylcyclopentadienyl), which feature a singly occupied lanthanide-lanthanide σ-bonding orbital of 5 d z 2 parentage, as determined by structural, spectroscopic, and computational analyses. Valence delocalization, wherein the d electron is equally shared by the two lanthanide centers, imparts strong parallel alignment of the σ-bonding and f electrons on both lanthanides according to Hund’s rules. The combination of a well-isolated high-spin ground state and large magnetic anisotropy in (Cp iPr5 ) 2 Dy 2 I 3 gives rise to an enormous coercive magnetic field with a lower bound of 14 tesla at temperatures as high as 60 kelvin. 

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2. Plasmonic catalysis with bi-resonant noble metal – CuFeS2 chalcopyrite hybrid structures

   https://doi.org/10.1088/1361-6528/add93f  

   Kundu, Koustav; Ouyang, Tianhong; Reinhard, Björn (May 2025, Nanotechnology)

   Both noble metal nanoparticles (NPs) and chalcopyrite (CuFeS2) nanocrystals (NCs) provide resonant absorption in the visible, albeit through different mechanisms. Coherent oscillations of free conduction band electrons give rise to localized plasmons in noble metal NPs, whereas collective oscillations of bound electrons are responsible for quasistatic resonances in CuFeS2 NCs. This manuscript reviews the photophysical and photocatalytic properties of both noble metal and chalcopyrite nanostructures as well as direct and indirect charge and energy transfer processes in hybrid structures containing noble metal NPs and either semiconductor NCs or molecular photosensitizers or photocatalysts. CuFeS2 NCs share structural similarities with conventional semiconductor NCs, but the availability of collective charge oscillations in the visible facilitates a resonant coupling to localized plasmons in NPs. Hybrid nanostructures containing both metal and chalcopyrite building blocks are examined as a platform for wavelength-dependent charge and energy transfer and bifunctional reactivity for enhanced plasmonic photocatalysis. 

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3. Characterizing Polyoxovanadate‐Alkoxide Clusters Using Vanadium K‐Edge X‐Ray Absorption Spectroscopy

   https://doi.org/10.1002/chem.202003625  

   Meyer, Rachel_L; Greer, Samuel_M; Blake, Anastasia_V; Cary, Samantha_K; Ditter, Alexander_S; Daly, Scott_R; Li, Feng; Kozimor, Stosh_A; Matson, Ellen_M; Mocko, Veronika; et al (December 2020, Chemistry – A European Journal)

   Abstract A number of technologies would benefit from developing inorganic compounds and materials with specific electronic and magnetic exchange properties. Unfortunately, designing compounds with these properties is difficult because metal⋅⋅⋅metal coupling schemes are hard to predict and control. Fully characterizing communication between metals in existing compounds that exhibit interesting properties could provide valuable insight and advance those predictive capabilities. One such class of molecules are the series of Lindqvist iron‐functionalized and hexavanadium polyoxovanadate‐alkoxide clusters, which we characterized here using V K‐edge X‐ray absorption spectroscopy. Substantial changes in the pre‐edge peak intensities were observed that tracked with the V 3d‐electron count. The data also suggested substantial delocalization between the vanadium cations. Meanwhile, the Fe^IIIcations were electronically isolated from the polyoxovanadate core. 

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4. Unfolding adsorption on metal nanoparticles: Connecting stability with catalysis

   https://doi.org/10.1126/sciadv.aax5101  

   Dean, James; Taylor, Michael G.; Mpourmpakis, Giannis (September 2019, Science Advances)

   Metal nanoparticles have received substantial attention in the past decades for their applications in numerous areas, including medicine, catalysis, energy, and the environment. Despite these applications, the fundamentals of adsorption on nanoparticle surfaces as a function of nanoparticle size, shape, metal composition, and type of adsorbate are yet to be found. Herein, we introduce the first universal adsorption model that accounts for detailed nanoparticle structural characteristics, metal composition, and different adsorbates by combining first principles calculations with machine learning. Our model fits a large number of data and accurately predicts adsorption trends on nanoparticles (both monometallic and alloy) that have not been previously seen. In addition to its application power, the model is simple and uses tabulated and rapidly calculated data for metals and adsorbates. We connect adsorption with stability behavior of nanoparticles, thus advancing the design of optimal nanoparticles for applications of interest, such as catalysis. 

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5. Hidden magnetism and split off flat bands in the insulator metal transition in VO2

   https://doi.org/10.1038/s41524-024-01382-8  

   Zhang, Xiuwen; Xiong, Jia-Xin; Zunger, Alex (September 2024, npj Computational Materials)

   Abstract Transition metald-electron oxides with an odd number of electrons per unit cell are expected to form metals with partially occupied energy bands, but exhibit in fact a range of behaviors, being either insulators, or metals, or having insulator-metal transitions. Traditional explanations involved predominantly electron-electron interactions in fixed structural symmetry. The present work focuses instead on the role of symmetry breaking local structural motifs. Viewing the previously observed V-V dimerization in VO₂as a continuous knob, reveals in density functional calculations the splitting of an isolated flat band from the broad conduction band. This leads past a critical percent dimerization to the formation of the insulating phase while lowering the total energy. In VO₂this transition is found to have a rather low energy barrier approaching the thermal energy at room temperature, suggesting energy-efficient switching in neuromorphic computing. Interestingly, sufficient V-V dimerization suppresses magnetism, leading to the nonmagnetic insulating state, whereas magnetism appears when dimerization is reduced, forming a metallic state. This study opens the way to design novel functional quantum materials with symmetry breaking-induced flat bands. 

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