A5011541321- Electron and X-Ray Spectroscopy Techniques
- Advanced Electron Microscopy Techniques and Applications
- Machine Learning in Materials Science
- Quantum Dots Synthesis And Properties
- Electronic and Structural Properties of Oxides
- Chalcogenide Semiconductor Thin Films
- Advanced X-ray Imaging Techniques
- 2D Materials and Applications
- Advancements in Battery Materials
- Physics of Superconductivity and Magnetism
- Magnetic and transport properties of perovskites and related materials
- X-ray Diffraction in Crystallography
- Integrated Circuits and Semiconductor Failure Analysis
- Nanocluster Synthesis and Applications
- Semiconductor materials and devices
- Magnetic properties of thin films
- Cephalopods and Marine Biology
- Advanced Battery Materials and Technologies
- Copper-based nanomaterials and applications
- Multiferroics and related materials
- Calcium Carbonate Crystallization and Inhibition
- Ionic liquids properties and applications
- Microstructure and mechanical properties
- Morphological variations and asymmetry
- Advanced Surface Polishing Techniques
Lawrence Berkeley National Laboratory
2019-2024
University of California, Berkeley
2024
H & N Instruments (United States)
2024
Cornell University
2014-2023
Molecular Foundry
2022
Berkeley College
2021
University of Florida
2017
Kavli Energy NanoScience Institute
2017
Brown University
2008
Decades of research focused on size and shape control iron oxide nanoparticles have led to methods synthesis that afford excellent over physical but comparatively poor magnetic properties. Popular based thermal decomposition organometallic precursors in the absence oxygen yielded particles with mixed phases, crystal defects, poorer than expected properties, including existence a thick "magnetically dead layer" experimentally evidenced by diameter significantly smaller diameter. Here, we show...
Nonlinear optics reveal how the chirality of ferroelectric vortices can be deterministically controlled using an electric field.
Significance Low-dimensional materials, such as 1T-TaS 2 , permit unique phases that arise through electronic and structural reshaping known, respectively, charge-density waves periodic lattice distortions (PLDs). Determining the atomic structure of PLDs is critical toward understanding origin these charge-ordered their effect on properties. Here we reveal microscopic nature at cryogenic room temperature in thin flakes using resolution scanning transmission electron microscopy. Real-space...
Significance Charge order is a modulation of the electron density and associated with unconventional phenomena, including colossal magnetoresistance metal–insulator transitions. Determining how lattice responds provides insights into nature symmetry ordered state. Scanning transmission microscopy can measure displacements picometer precision, but its use has been limited to room-temperature phases only. Here, we demonstrate high-resolution imaging at cryogenic temperature map evolution...
Magic-sized clusters (MSCs) are renowned for their identical size and closed-shell stability that inhibit conventional nanoparticle (NP) growth processes. Though MSCs have been of increasing interest, understanding the reaction pathways toward nucleation stabilization is an outstanding issue. In this work, we demonstrate high concentration synthesis (1000 mM) promotes a well-defined pathway to form high-purity (greater than 99.9 percent). The resistant typical dissolution Based on insights...
Scanning transmission electron microscopy (STEM) allows for imaging, diffraction, and spectroscopy of materials on length scales ranging from microns to atoms. By using a high-speed, direct detector, it is now possible record full 2D image the diffracted beam at each probe position, typically grid positions. These 4D-STEM datasets are rich in information, including signatures local structure, orientation, deformation, electromagnetic fields other sample-dependent properties. However,...
Crystalline materials used in technological applications are often complex assemblies composed of multiple phases and differently oriented grains. Robust identification the orientation relationships from these samples is crucial, but information extracted diffraction condition probed by an electron beam incomplete. We therefore have developed automated crystal mapping (ACOM) procedure which uses a converged probe to collect patterns locations across sample. provide algorithm determine each...
Abstract In charge-ordered phases, broken translational symmetry emerges from couplings between charge, spin, lattice, or orbital degrees of freedom, giving rise to remarkable phenomena such as colossal magnetoresistance and metal–insulator transitions. The role the lattice in states remains particularly enigmatic, soliciting characterization microscopic behavior. Here we directly map picometer scale periodic displacements at individual atomic columns room temperature manganite Bi 0.35 Sr...
Abstract A fast, robust pipeline for strain mapping of crystalline materials is important many technological applications. Scanning electron nanodiffraction allows us to calculate maps with high accuracy and spatial resolutions, but this technique limited when the beam undergoes multiple scattering. Deep-learning methods have potential invert these complex signals, require a large number training examples. We implement Fourier space, complex-valued deep-neural network, FCU-Net, highly...
Determining the degree and spatial extent of structural order in liquids is a grand challenge. Here, we are able to resolve model organic electrolyte 1 M lithium hexafluorophosphate (LiPF 6 ) dissolved 1:1 (v/v) ethylene carbonate:diethylcarbonate by developing an integrated method liquid-phase transmission electron microscopy (TEM), cryo-TEM operated at −30°C, four-dimensional scanning TEM, data analysis based on deep learning. This study reveals presence short-range (SRO) high–salt...
New methods are developed for the synthesis and surface modification of colloidal PbS nanosheets. We find that residual acetate is a crucial reagent formation nanosheets by existing syntheses. The amount in reaction mixtures is, however, difficult to control, which substantially reduces reproducibility synthesis. To solve this problem, we develop an acetate-free synthetic method yield with lateral dimensions several hundred nanometers. thickness shape can be readily tuned varying parameters....
Abstract We describe the development, operation, and application of 4D Camera—a 576 by pixel active sensor for scanning/transmission electron microscopy which operates at 87,000 Hz. The detector generates data ∼480 Gbit/s is captured dedicated receiver computers with a parallelized software infrastructure that has been implemented to process resulting 10–700 Gigabyte-sized raw datasets. back illuminated provides ability detect single events accelerating voltages from 30 300 kV. Through...
Epitaxially connected superlattices of self-assembled colloidal quantum dots present a promising route toward exquisite control electronic structure through precise hierarchical structuring across multiple length scales. Here, we uncover propagation disorder as an essential feature in these systems, which intimately connects order at the atomic, superlattice, and grain Accessing theoretically predicted exotic states highly tunable minibands will therefore require detailed understanding...
A Twinning Induced Plasticity (TWIP) steel with a nominal composition of Fe-16.4Mn-0.9C-0.5Si-0.05Nb-0.05V was deformed to an engineering strain 6%. The around the deformation twins were mapped using 4D-STEM technique. Strain mapping showed large average elastic approximately 6% in directions parallel and perpendicular twinning direction. However, comprised several hot spots even larger strains up 12%. These could be attributed high density sessile Frank dislocations on twin boundary...
Exploratory synthesis has been the main generator of new inorganic materials for decades. AI-assisted discovery is possible, but human-AI collaboration should be refined according to their respective strengths.
Summary The size of whole Rhodobacter sphaeroides prevents 3D visualization centermost chromatophores in their native environment. This study combines cryo‐focused ion beam milling with cryo‐electron tomography to probe vesicle architecture both situ and 3D. Developing are membrane‐bound buds that remain topological continuity the cytoplasmic membrane detach into vesicles when mature. Mature closest cell wall typically isolated vesicles, whereas either linked neighboring or contain smaller,...
py4DSTEM is a free, open source, python-based data analysis package for the emerging field of fourdimensional scanning transmission electron microscopy (4D-STEM).In 4D-STEM, beam rastered across sample and diffraction pattern collected at each scan position, yielding highly information-rich datasets which can be used to virtually recreate images that map orientation, local lattice parameters, strain, short/medium range ordering, or reconstruct electrostatic potential itself [1].These easily...