The study of first-order structural transformations has been great interest to scientists in many disciplines. Expectations from phase-transition theory are that the system fluctuates between two equilibrium structures near transition point and region broadens small crystals. We report direct observation fluctuations within a single nanocrystal using transmission electron microscopy. observed trajectories individual nanocrystals with atomic resolution, which reveal details fluctuation...

Many ultrafast solid phase transitions are treated as chemical reactions that transform the structures between two different unit cells along a reaction coordinate, but this neglects role of disorder. Although diffraction provides insights into atomic dynamics during such transformations, alone probes an averaged cell and is less sensitive to randomness in transition pathway. Using total scattering femtosecond x-ray pulses, we show disordering photoexcited vanadium dioxide (VO2) central...

Angle-resolved photoemission is employed to measure the band structure of TiSe2 in order clarify nature ( 2 x 2) charge density wave transition. The results show a very small indirect gap normal phase transforming into larger at different location Brillouin zone. Fermi surface topology irrelevant this case. Instead, electron-hole coupling together with novel Jahn-Teller effect drives

Electronic chirality near the Dirac point is a key property of graphene systems, which revealed by spectral intensity patterns as measured angle-resolved photoemission spectroscopy under various polarization conditions. Specifically, strongly modulated circular for monolayer (bilayer) rotate ±90° (±45°) in changing from linearly to circularly polarized light; these angles are directly related phases wave functions and thus visually confirm Berry's phase π (2π) around point. The details...

Quantum-well states have been observed with angle-resolved photoemission for Ag overlayers thicknesses up to 40 monolayers epitaxially grown on Au(111). These are within an energy window of 1 eV. The complementary system, Au Ag(111), exhibits no such states. results can be explained in terms the band-structure mismatch between and Ag. coherence length quasibound quantum-well resonances will discussed.

We have studied the structural stability of thin silver films with thicknesses N = 1 to 15 monolayers, deposited on an Fe(100) substrate. Photoemission spectroscopy results show that 1, 2, and 5 monolayer are structurally stable for temperatures above 800 kelvin, whereas other unstable bifurcate into a film +/- at around 400 kelvin. The in agreement theoretical predictions consider electronic energy quantum well associated particular thickness as significant contribution stability.

Atomically uniform Pb films are successfully prepared on Si(111), despite a large lattice mismatch. Angle-resolved photoemission measurements of the electronic structure show layer-resolved quantum well states which can be correlated with dramatic variations in thermal stability. The odd film thicknesses N = 5, 7, and 9 monolayers sharp states. even 6 8 do not, but much more stable than thicknesses. This correlation is discussed terms total energy calculation Friedel-like oscillations properties.

Photoemission studies of Ag deposits on cleaved n- and p-type GaAs for coverages from ∼0.003 to 20 monolayers indicate clustered growth undetectable chemical interactions with the substrate. The position surface Fermi level changed throughout deposit range. data is inconsistent most existing Schottky barrier models. results are interpreted in terms donor- acceptorlike interface states which characteristic clusters but modified by screening at interface. Values 0.89 eV n-type 0.35 material...

The functionalities of a wide range optical and opto-electronic devices are based on resonance effects active tuning the amplitude wavelength response is often essential. Plasmonic nanostructures an efficient way to create resonances, prominent example extraordinary transmission (EOT) through arrays nanoholes patterned in metallic film. Tuning resonances by heating, applying electrical or signals has proven be more elusive, due lack materials that can induce modulation over broad spectral...

Spin-polarized gapless surface states in topological insulators form chiral Dirac cones. When such materials are reduced to thin films, the on two faces of film can overlap and couple by quantum tunneling, resulting a thickness-dependent insulating gap at point. Calculations for freestanding Sb with thickness four atomic bilayers yield 36 meV, yet angle-resolved photoemission measurements grown Si(111) reveal no formation. The surprisingly robust cone is explained calculations terms...

The strength of electron-phonon coupling in atomically uniform films Ag on Fe is determined by angle-resolved photoemission from quantum well states these over a wide temperature range. As the film thickness reduced, contributions surface and interface should become more important, and, experimentally, large enhancement with superimposed oscillations observed. An analysis indicates that this an effect.

We report time-resolved studies of hydrogen bonding in liquid H2O, response to direct excitation the O–H stretch mode at 3 μm, probed via soft X-ray absorption spectroscopy oxygen K-edge. This approach employs a newly developed nanofluidic cell for transient phase. Distinct changes near-edge spectral region (XANES) are observed, and indicative temperature rise 10 K following laser rapid thermalization vibrational energy. The heating occurs constant volume associated increase internal...

Topological materials have unusual surface spin properties including a net current protected by the bulk symmetry properties. When such are reduced to thin films, their gapless spin-polarized states must connect, analytic continuation, bulk-derived quantum-well states, which spin-unpolarized in centrosymmetric systems. The nature of this passage model system, Sb is investigated. Angle-resolved photoemission shows smooth transition, while calculations elucidate correlated evolution and charge...

Radiotherapy (RT) toxicities can impair survival and quality of life, yet remain understudied. Real-world evidence holds potential to improve our understanding toxicities, but toxicity information is often only in clinical notes. We developed natural language processing (NLP) models identify the presence severity esophagitis from notes patients treated with thoracic RT. Our corpus consisted a gold-labeled data set 1,524 124 lung cancer RT, manually annotated for Common Terminology Criteria...

<sec> <title>BACKGROUND</title> Patients with mood or psychotic disorders experience high rates of unplanned hospital readmissions. Predicting the likelihood readmission can guide discharge decisions and optimize patient care. </sec> <title>OBJECTIVE</title> The purpose this study is to evaluate predictive power structured variables from electronic health records (EHRs) for all-cause across multiple sites within Mass General Brigham (MGB) systems assess transportability prediction models...

Recent progress in large language models (LLMs) has enabled the automated processing of lengthy documents even without supervised training on a task-specific dataset. Yet, their zero-shot performance complex tasks as opposed to straightforward information extraction remains suboptimal. One feasible approach for with lengthy, input is first summarize document and then apply fine-tuning summary. However, summarization process inevitably results some loss information. In this study we present...

The work function of atomically uniform Ag films grown on Fe(100) is measured as a film thickness. It shows layer-resolved variations result quantum confinement the valence electrons. A first-principles calculation reproduces observed except for very thin (one and two monolayers), differences can be attributed, in part, to strain effects caused by lattice mismatch between Fe. These results illustrate close interaction interface surface properties.

A precision determination of the number dimer atoms on Si(100)-(2\ifmmode\times\else\texttimes\fi{}1) surface which contribute to 2p core-level shift as measured by high-resolution photoemission is possible with an in situ comparison Si(111)-(7\ifmmode\times\else\texttimes\fi{}7). By correlating distinct features Si(111)-(7\ifmmode\times\else\texttimes\fi{}7) spectrum known structural (7\ifmmode\times\else\texttimes\fi{}7) surface, core 0.92\ifmmode\pm\else\textpm\fi{}0.07 monolayers....

The Sb saturation of Si(111) and Si(001) was found by angle-resolved photoemission to allow the measurement bulk band-dispersion relations along high-symmetry $\ensuremath{\Gamma}\ensuremath{-}\ensuremath{\Lambda}\ensuremath{-}L$ $\ensuremath{\Gamma}\ensuremath{-}\ensuremath{\Delta}\ensuremath{-}X$ directions over a wide photon-energy range. Core-level spectroscopy revealed that Si atoms in near-surface region are converted exhibit bulklike atomic arrangement after coverage. Strain reduction...

Topological surface states are protected against local perturbations, but this protection does not extend to chemical reaction over the whole surface, as demonstrated by theoretical studies of oxidation ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ and its effects on spin polarization current. While chemisorption ${\mathrm{O}}_{2}$ largely preserves topological states, with atomic O removes original yields two new sets states. One set forms a regular Dirac cone is topologically trivial. The other...

The electronic structure of Bi(110) thin films as a function film thickness is investigated by first-principles calculations, angle-resolved photoemission spectroscopy, and scanning tunneling microscopy. Energy minimization in the calculation reveals significant atomic relaxation rebonding at surface. calculated surface energy for relaxed structures indicates that consisting odd numbers layers are inherently unstable tend to bifurcate into domains neighboring even layers. This theoretical...

Unsupervised domain adaptation (UDA) is the task of modifying a statistical model trained on labeled data from source to achieve better performance target domain, with access only unlabeled in domain. Existing state-of-the-art UDA approaches use neural networks learn representations that can predict values subset important features called "pivot features." In this work, we show it possible improve these methods by jointly training representation learner learner, and examine importance...

Epitaxial Ag(100) films have been grown on highly perfect Fe(100) substrates by deposition at low temperatures followed annealing. Precise control of the process results in film thicknesses exactly $N$ atomic layers ( an integer up to 39) over a macroscopic distance $(\ensuremath{\sim}1\mathrm{mm})$. The elimination layer fluctuation, which has generally believed be impossible such large thicknesses, allows us observe atomic-layer resolved quantum well states. Such states exhibit extremely...