Nano Letters最新文献

Chiral materials, which lack inversion and mirror symmetries,hostspin textures in momentum space that give rise to current-inducedspin polarization. In bulk Te, symmetry restricts the induced spinpolarization to the chiral axis, allowing unidirectional magnetoresistance(UMR) only when the magnetic field is aligned with this direction.Here, we demonstrate an unconventional UMR in chiral Te nanosheetsthat emerges under a magnetic field transverse to the chiral axis.The unconventional UMR exhibits nearly linear magnetic-field and currentdependences and reverses sign with opposite crystal handedness, confirmingits intrinsic chiral origin. First-principles calculations explainthe unconventional UMR by out-of-plane spin polarization induced bysymmetry reduction in Te nanosheets. Furthermore, electrostatic gatingexperiments demonstrate that the unconventional UMR is governed bythe electronic structure near the Fermi level. These results establishsymmetry reduction and Fermi-level control as effective routes togenerating multiaxis spin polarization in chiral materials.

Electrochemical urea synthesis from CO₂ andNO₃^– offers a low-energy, green alternativeto thetraditional Bosch–Meiser route. However, mismatched adsorptionof C/N intermediates, complex proton-coupled electron transfer, andhigh C–N coupling barrier on conventional single- or dual-sitecatalysts greatly hinder catalytic efficiency. Herein, we proposeda novel, enzyme-mimetic tri-site design to spatially decouple CO₂ → *CO, NO₃^– →*NH₂, and subsequent C–N coupling. As a prototype,tri-site Sn-doped CuO_x nanoparticles wereconstructed, where Cu¹ stabilizes *CO and suppresses furtherprotonation. Cu⁰ drives the stepwise reduction of NO₃^– to *NH₂OH, which is rapidlyprotonated into *NH₂ and spills over to Sn site. Eventually,*CO and *NH₂ undergo efficient C–N coupling to formurea. Therefore, Sn/CuO_x catalyst deliversa urea yield of 4824 μg h^–1 mg_cat^–1, 26.8% Faradaic efficiency, 69.3% C-selectivity,and 30.5% N-selectivity, outperforming the bare CuO_x counterpart. This work demonstrates a promising enzyme-mimeticand tandem electrocatalysis paradigm for green fertilizer synthesis.

The reversible formation/decompositionof Li₂O₂ is central to nonaqueous lithium–oxygen(Li–O₂) batteries, where sluggish oxygen redox kineticscauses largepolarization and limited capacity, undermining their otherwise hightheoretical energy density. Here, a high-entropy sulfide catalyst((CoFeNiMnZn)₃S₄) is fabricated via a multisteplow-temperature strategy. The high-entropy-induced lattice strainregulates the electronic structure and d-band center of the catalyst,thereby optimizing the adsorption behavior of intermediates. Unlikethe film- or toroid-like discharge products observed on quaternarycatalyst cathodes, nanosheet-like Li₂O₂ is generatedon the (CoFeNiMnZn)₃S₄ cathode, promoting highlyreversible discharge–recharge processes. When employed as cathodesin Li–O₂ batteries, the (CoFeNiMnZn)₃S₄ delivers superior electrochemical performance, includinga high discharge capacity (17874 mAh g^–1), a lowoverpotential of 0.57 V, and enhanced cycling stability (over 420cycles at 1000 mA g^–1). This work establishes anew paradigm for designing high-entropy sulfide electrocatalysts towardhigh-performance Li–O₂ batteries.

Thermochromic coatingsenable passive building energymanagement,but approaches lack broad tuning ranges, continuous tunability, practicaltransition temperatures, or scalability. This work introduces a dual-layerthermochromic coating (DLTC) that functionally decouples the blackand white states between layers, achieving a transition temperatureof 25 °C, solar reflectance tunability of 36.7% (51.4–88.1%),and visible reflectance tunability of 81.2% (6.0–87.2%). DLTCintegrates a thin (∼68 μm) black-to-translucent topcoaton an opaque ultrawhite basecoat (>400 μm). Under cold conditions,the topcoat darkens, absorbing solar radiation; as the temperaturerises, the topcoat becomes translucent, exposing the ultrawhite basecoatand producing a radiative cooling surface. Outdoor tests show up to23 °C cooling relative to a black roof in hot weather and 12°C warming relative to a white roof in cold weather. EnergyPlussimulations predict HVAC energy savings over traditional gray andwhite cool roofs across U.S. climate zones.

Organic radical chains provide anatomically preciseplatform forrealizing interacting quantum spin nanostructures, but controllingthe local fate of fractional boundary degrees of freedom at internalinterfaces remains challenging. Here, we investigate interfaces betweena dimerized spin-1/2 sector and a Hund-coupled effective Haldane spin-1sector within a trioxoazatriangulene-based parent chain. Althoughthe constituent fractional boundary moments are individually established,their many-body response at the heterojunction depends sensitivelyon the bond-level termination registry. In one geometry, adjoiningspin-1/2-like boundary contributions locally compensate and quenchthe interfacial response, whereas a parity-shifted registry leavesan uncompensated localized spin-1/2-like mode. Two such internal modesof a finite embedded Haldane domain hybridize with an approximatelyexponentially decreasing splitting. The active and quenched junctionstherefore exhibit distinct local low-energy spin responses. Theseresults identify termination parity and bond-level interface registryas practical control parameters for activating, locally quenching,and coupling fractional spin modes in organic quantum spin nanostructures.