Surface Engineering at the Nanoscale

🔬 Why Understanding Nanoalloy Formation Matters Nanoalloys — ultra-small particles made from two or more metal atoms — are among the most promising building blocks for next-generation catalysts, sensors, and energy materials. At these scales, of 1 to 2 nanomater radius, every atom and electron counts. Their unique properties do not simply come from the bulk metals they’re made of, but from how those atoms arrange themselves. For example, when the particle is about 1 nanometer in size, quantum effects and surface energy start to dominate their physical-chemical properties, and hence, their stability. This makes predicting their physical-chemical behavior far more complex. Few questions to provide an example of the complexity: Which metal prefers the surface? Which stays in the core? Why do some compositions form mixed alloys while others form clear core–shell structures? In our recent study (https://lnkd.in/dEZSEQ5f), we used density functional theory (DFT) — a state-of-the-art quantum mechanical method — to explore the structural, energetic, and electronic properties of 55-atom nanoalloys made of aluminum, copper, zinc, and silver. By combining clustering algorithms with design principles, we created a wide range of candidate structures and compared their stabilities. Our results show that certain combinations, like Al–Cu and Al–Ag, are especially stable and naturally adopt specific shapes. For example: --- Al₄₂Cu₁₃ tends to form an “onion-like” configuration. --- Al₄₂Ag₁₃ prefers a “core–shell” arrangement, with one metal concentrated at the center and another at the surface. By running Spearman’s correlation analysis, we also identified which structural descriptors most strongly relate to energy stability — such as the number of under-coordinated atoms, effective coordination number, average bond length, and chemical order parameter. This type of analysis tells us not just what structures form, but why they are stable. Several other properties, including particle volume, binding energy, and average bond length, showed clear linear relationships with composition. This suggests we can predictably tune nanoalloy properties just by adjusting the mixture of metals. Why does this matter? Because the surface composition and internal structure directly control how nanoalloys behave in real applications — from catalytic activity to electronic conductivity. By understanding the underlying physical-chemistry mechanisms, we can move from trial-and-error synthesis to rational design of nanoparticles with exactly the properties we want. This kind of fundamental research is essential for making nanoalloys a reliable platform for cleaner energy, smarter sensors, and more efficient industrial processes. #Nanoalloys #Nanoscience #MaterialsScience #Catalysis #SurfaceScience #DFT #Research #Innovation #Energy

ONE NANOMETER STABILIZATION OF ELECTRON SPIN: UNIFIED FRAMEWORK FOR PSH-BASED SPINTRONICS The pursuit of energy-efficient, scalable spin-based information processing has intensified amid the rising computational demands of artificial intelligence and quantum technologies. Spintronics, which exploits the quantum spin degree of freedom rather than charge, offers a compelling alternative to conventional silicon electronics. However, realizing robust spin transport requires materials that support large spin splitting and persistent spin helix (PSH) textures, states where spin coherence is preserved despite momentum scattering. Such textures are rare due to stringent symmetry constraints, limiting the material palette for spintronic device engineering. Recent experimental breakthroughs by researchers at Rice University have demonstrated that mechanical deformation, specifically nanoscale creases and wrinkles, in atomically thin materials such as Molybdenum Ditelluride (MoTe₂) can induce PSH states with unprecedented spin coherence. These deformations generate flexoelectric polarization fields that break inversion symmetry and stabilize spin textures even under electron scattering. The resulting spin precession length of ~1 nm represents a record-setting compactness, enabling ultraminiaturized spintronic architectures. Complementing these findings, computational investigations established a design principle for inducing large and unidirectional Rashba SOC in undulated 2D materials. Using first-principles calculations and two-band analytical models, it was shown that net curvature may integrate to zero when the associated band shifts Δ ∝ κ² ensure non-vanishing spin splitting. This interplay yields isolated spin-polarized states with minimal dephasing, satisfying the conditions for PSH formation. This effect was demonstrated in group VI transition metal dichalcogenides (TMDs), particularly MoTe₂, which combines high atomic number (Z) for strong SOC with mechanical flexibility. The simulations reveal that Rashba spin splitting up to ~0.16 eV and PSH textures with spin precession lengths as short as ~1 nm, aligning with experimental observations. These results underscored the role of flexoelectricity and asymmetric hybridization in shaping spin landscapes, and establish surface topography as a tunable parameter for spintronic functionality. This unified framework, bridging quantum spin physics, flexoelectric mechanics, and topographical engineering, offers a scalable route to design PSH-enabled materials. It transforms the challenge of symmetry-constrained spin textures into an opportunity for deterministic control via mechanical deformation. The implications extend to adaptive spin logic, spin field-effect transistors, and quantum computing platforms based on Majorana modes, where Rashba SOC plays a pivotal role to achieve high-performance, low-power information processing beyond the limits of silicon. # https://lnkd.in/e-PAJjxr

Recent advancements in atomic layer processing, particularly in Atomic Layer Deposition (ALD) and Atomic Layer Etching (ALE), have significantly improved the precision of gold manipulation at the atomic scale. Professor Seán Barry’s team pioneered a plasma-enhanced ALD (PEALD) method for depositing gold using a trimethylphosphine-supported gold precursor and plasma activation, which enables uniform gold films ideal for complex applications. The University of Helsinki recently introduced a thermal ALD process for 3D gold coatings using Me₂Au(S₂CNEt₂) and ozone, broadening the application range with continuous and conductive films. Complementing these deposition methods, Professor Steven M. George’s team developed a thermal ALE process for gold etching, using a two-step chlorination and ligand addition sequence to achieve controlled, self-limiting atomic removal. These combined breakthroughs allow for nanoscale precision in depositing and etching gold, with potential applications in electronics, catalysis, and surface engineering. #gold #ALDep #ALEtch #semiconductor Sean Barry University of Colorado Boulder@Carleton University Mikko Ritala

🔬 #FluorescenceFriday 🎃 From spooky-colored clusters to nanoscale anchors Cells don’t just stick, they interpret. This week, we dive into the fascinating world of #cell–matrix interactions, from my PhD research in Prof. Duncan Sutherland’s group at Aarhus University, where we explored how #nanoscale protein patterning modulates integrin-mediated adhesion. In the fluorescent image, we see human #skin cells interacting with a nanopatterned surface functionalized with laminin, a key component of the basement membrane: 🟠 Integrin α6: clustering in bright nano-puncta 🟣 DAPI: nuclear staining By mimicking #hemidesmosome-like structures, these nanopatterns guide integrin clustering, enabling cells to form stable, specific attachments. These engineered biointerfaces don’t just enhance adhesion, they influence how cells spread, signal, and ultimately differentiate. 🔬 In the accompanying SEM image, captured at higher magnification, you can literally see cellular protrusions making contact with individual nanopatterns, offering a striking visualization of nano-biointerface recognition in action. This is a vivid reminder that in building complex in vitro models (CIVM), we must consider all dimensions of the cellular microenvironment, not just #biochemical or #biomechanical cues, but also the nano/micro-architecture of the interface itself. 🧠 Why this matters: By adjusting the size, spacing, and type of protein ligand, we can precisely tune the cell-matrix interaction landscape, regulating cell phenotype and behavior. To learn more about our approach and insights, check out the links below: -https://lnkd.in/dva9CAuc -https://lnkd.in/g7kFEe2W #NanoBiointerfaces #Hemidesmosomes #SkinCells #Nanopatterning #SEM #Biointerfaces #CellAdhesion #FluorescenceMicroscopy #MicroscaleBiointerfaces #ProteinLigands #CellMatrixInteraction #Mechanobiology #Biomaterials #TissueEngineering #InVitroModels #HighResolutionImaging #Laminin #PhDResearch #AarhusUniversity #DuncanSutherlandGroup #ScientificImaging #HalloweenScience #CellPhenotype #Nanoengineering #3DCellCulture #RegenerativeMedicine #EngineeringBiology #AdvancedMicroscopy

🚀 Breaking New Ground in Nanoscale Science! 🚀 I am excited to share our latest results from SLAC National Accelerator Laboratory and Stanford University capturing the spatiotemporal evolution of surface charges on silicon dioxide (SiO₂) nanoparticles with femtosecond precision! The related article led by my former graduate student Ritika Dagar and postdoc Wenbin Zhang was published today in Science Advances. For the first time, we used time-resolved reaction nanoscopy, developed in our group, to see how surface charges redistribute and affect molecular bonds. The study suggests a need to rethink nanoscale surface charge processes, influencing everything from catalyst design to photocatalytic systems. The findings can help to design new nanomaterials with tailored properties, impacting energy storage, sensing, and biomedicine. Join us in celebrating this milestone that promises to redefine our grasp of charge-driven phenomena! For more information, read the article here: https://lnkd.in/gAFJ6nXp The research was supported by the U.S. Department of Energy Office of Science. #Nanoscience #ResearchBreakthrough #ChargeDynamics #Innovation #ScienceAdvances #SLAC #StanfordUniversity #MaterialsScience

Nanoparticles often undergo thermally driven phase transitions and shape shifting spatial transformation resulting in a thermodynamically stable structures at that temperature. In case of crystalline nanoparticles, these transformations are usually anisotropic, meaning that they are surface dependent. This surface dependency of anisotropic phase transitions is attributed to the work function, surface energy and chemical potential of different crystal facets. When heated, these structures become unstable and begin to transform to an isotropic structure with high thermodynamic stability at a large range of temperature. Investigating these structural phase transitions at atomic scale may provide why some catalysts work terribly at high temperatures and why some catalysts fail to reactivate by thermal treatment. Researchers from Institute for basic science (IBS) have used environmental transmission electron microscopy (ETEM) to observe these structural transformations and geometric shape shifts in gold nanoparticles at atomic scale using phase-contrast microscopy. They studied two types of gold nanoparticles, gold nanorods and triangular gold nanoplates. Above 180°C at 1 mbar O₂, surface encapsulating thiol ligands underwent surface desorption exposing the gold surfaces to the oxygen environment. In absence of any surface stabilizing ligands, surfaces atoms started to diffuse around transforming the gold nanoparticles to more thermodynamically stable structures. Nanorods were found to transform to nanoellipsoids whereas nanotriangles were found to transform to nanohexagons through the truncation of their vertices. However, the mechanisms of surface atom diffusion are different in these two cases. In case of nanorods, indiscriminate surface migration of vertex atoms to the sides was found to be driven by the formation of multiple intermediate high-index facets; on the other hand, selective layer-by-layer migration of vertex atoms to the triangular faces was found to have occurred in case of nanotriangles until a hexagonal shape is attained. The thermodynamic driving force here is the minimization of the low-coordinated gold surface atoms that anticipates the final spherical shape of the particles. The triangular geometry of the nanotriangles allowed the {111} surfaces on all faces remain intact during the transition to hexagonal geometry. ETEM experiments were conducted on an aberration-corrected Thermo Fisher Scientific Titan ETEM G2 operated at 300 keV and equipped with a Gatan Inc. UltraScan 1000XP CCD detector. In-situ heating inside the microscope was conducted with a Protochips Fusion in-situ heating TEM holder. Video description is in the comments. Read the interesting findings published in the Journal of Physical Chemistry C. https://lnkd.in/dPHrTx2C #phasetreansitions #surfaceatomdiffusion #phasecontrast #insituTEM #ETEM #Fusion #UltraScan1000XP #electronmicroscopy

Automated construction of artificial lattice structures with designer electronic states Scanning tunneling microscopes (STMs) can move individual atoms and molecules to build artificial quantum materials, one building block at a time. In principle, that lets us “draw” band structures on a surface—creating lattices with properties that don’t exist in nature. In practice, it’s slow, fragile work: every move depends on carefully tuned voltage, current, tip shape, and drift correction, and a single bad manipulation can ruin hours of progress. Ganesh Narasimha and coauthors present an automated STM workflow that uses deep reinforcement learning to push CO molecules on a Cu(111) surface into precise positions, with minimal human intervention. A YOLO-style object detector first locates the molecules; a linear assignment algorithm matches them to target sites; and a DDPG agent chooses the manipulation parameters—bias, tunneling current, and speed—while path-planning routines keep motion aligned with low-energy crystallographic directions and correct for drift. Using this setup, the system assembles an extended artificial graphene lattice and scanning tunneling spectroscopy reveals a clear Dirac point in its electronic structure, confirming that the desired “designer” band structure has been realized. While still semi-autonomous—tip conditioning and some parameter tuning remain human-guided—the approach points toward STM as an executable backend for inverse design. Generative or evolutionary models could propose artificial lattices with target quantum properties, and RL-controlled STM would build and test them directly on the surface. That moves atomically precise quantum matter engineering closer to a regime where structures are not just imagined and simulated, but automatically fabricated and characterized in closed loop. Paper: https://lnkd.in/eWPVwAKp #AIforScience #ReinforcementLearning #ScanningTunnelingMicroscopy #QuantumMaterials #ArtificialLattices #Graphene #Nanotechnology #Automation #LabAutomation #DeepLearning #YOLO #QuantumEngineering #SurfaceScience #MaterialsScience #InverseDesign #AtomicScale

🚀 When light becomes a manufacturing tool at the scale of life We often talk about precision engineering. But what happens when precision reaches the nanometer scale — small enough to interact with the human body? Enter femtosecond lasers. A femtosecond is 10⁻¹⁵ seconds. At this timescale, lasers don’t just cut metal — they reshape it with almost no heat impact. This enables ultra-precise structuring of metals without damaging surrounding material. And this is not just a lab curiosity — it’s already being applied in medical technologies that operate inside blood vessels. 🔬 What does this enable in practice? 1. Vascular stents Femtosecond lasers are used to cut and structure metals like nitinol with extreme precision: Complex mesh geometries for flexibility and strength Smooth, damage-free edges Surface textures that can reduce thrombosis risk 2. Microfluidic implants & drug delivery systems Lasers can engrave microscopic channels into metal and polymer surfaces: Controlled drug release inside the bloodstream Implantable diagnostic systems Lab-on-chip devices operating at micro-scale 3. Surface-functionalized implants Femtosecond lasers can “program” how a surface interacts with biology: Nano-patterns that promote cell adhesion Structures that reduce bacterial growth Textures that influence blood flow and protein interaction 4. Miniaturized surgical tools The same technology enables: Microneedles for minimally invasive treatments Ultra-sharp surgical components Tools designed for navigating extremely small anatomical pathways 💡 The bigger shift We are moving from manufacturing devices to engineering interfaces with living systems. 👉 Not just shaping metal 👉 But controlling how it behaves inside the human body Femtosecond lasers are one of the key technologies making this possible. #DeepTech #MedTech #AdvancedManufacturing #Foresight #Innovation #LaserTechnology #FemtosecondLaser #Photonics #PrecisionEngineering #Microfabrication #Nanotechnology #BiomedicalEngineering #MedicalDevices #HealthTech #Biotech #Implants #Microfluidics #FutureOfHealthcare #NextGenTech #TechInnovation #EngineeringExcellence #Industry40 #DigitalManufacturing