A5034245797- Electronic and Structural Properties of Oxides
- Surface and Thin Film Phenomena
- Magnetic and transport properties of perovskites and related materials
- Magnetic properties of thin films
- Ferroelectric and Piezoelectric Materials
- Luminescence Properties of Advanced Materials
- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Solid State Laser Technologies
- Electron and X-Ray Spectroscopy Techniques
- Graphene research and applications
- Semiconductor materials and devices
- Glass properties and applications
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Battery Materials and Technologies
- Semiconductor materials and interfaces
- Nuclear materials and radiation effects
- Rare-earth and actinide compounds
- Nuclear Materials and Properties
- X-ray Diffraction in Crystallography
- Nuclear Physics and Applications
- 2D Materials and Applications
- Solid-state spectroscopy and crystallography
- High-pressure geophysics and materials
- Thermal Expansion and Ionic Conductivity
Argonne National Laboratory
2016-2025
Advanced Photon Source
2023
Advanced Photonix (United States)
2023
Institute of High Energy Physics
2021
Chinese Academy of Sciences
2021
Institute of Physics
2021
University of Chinese Academy of Sciences
2021
Northwestern University
2016
University of Illinois Urbana-Champaign
1999-2008
Goodwin College
1995-2007
The square-planar nickelates are a class of superconductors analogous to the cuprates and promise provide insight into pairing mechanism in high-temperature superconducting oxides. parent phase doped films is ${\mathrm{NdNiO}}_{2}$, which prepared by reducing ${3}^{+}$ Ni ${\mathrm{NdNiO}}_{3}$ films. In this paper, we develop an ultrahigh vacuum reduction method using aluminum deposited on top monitor process real time through situ crystal truncation rod measurements diffraction x-ray...
We report the appearance of superconductivity in single-unit-cell Nd 6 Ni 5 O 12 , exhibiting a transition temperature similar to that thicker films. In situ synchrotron x-ray scattering performed during growth parent phase, 16 shows necessary layer-by-layer deposition sequence does not follow formula unit but an alternate order due relative stability perovskite cell. exploit this insight grow ultrathin heterostructures and conduct studies topotactic reduction, finding formation...
The charge-density-wave transition in TiSe (2), which results a commensurate (2x2x2) superlattice at temperatures below approximately 200 K, presumably involves softening of zone-boundary phonon mode. For the first time, this phonon-softening behavior has been examined over wide temperature range by synchrotron x-ray thermal diffuse scattering.
The evolution with $x$ of the monoclinic-to-tetragonal transition temperature and room-temperature monoclinic structures system ${\mathrm{V}}_{1\ensuremath{-}x}{\mathrm{Cr}}_{x}{\mathrm{O}}_{2}$ have been reexamined extended to cover entire solid-solution range $0\ensuremath{\le}x<0.20$. space group phase changes from $\frac{P{2}_{1}}{c}$ at $x=0$ $\frac{C2}{m}$ for $0.005\ensuremath{\le}x\ensuremath{\le}0.065$ $\frac{P2}{m}$ $0.07\ensuremath{\le}x<0.20$. structure is determined first time....
Real-time in situ x-ray studies of continuous Pb deposition on Si(111)-(7x7) at 180 K reveal an unusual growth behavior. A wetting layer forms first to cover the entire surface. Then islands a fairly uniform height about five monolayers form top and grow fill The then switches layer-by-layer mode upon further deposition. This behavior alternating island can be attributed spontaneous quantum phase separation based first-principles calculation system energy.
A beam of monochromatic synchrotron x-ray incident on a silicon wafer creates rich intensity pattern behind the that reflects cross section scattering by thermally populated phonons. least-squares fit patterns based lattice dynamics calculation yields phonon dispersion relations over entire reciprocal space. This simple and efficient method is suitable for studies in essentially all materials, complements traditional neutron technique.
We have studied the nanoscale structural evolution of Pb films grown at 110 K on a Si(111) substrate as they are annealed to increasingly higher temperatures. Surface x-ray diffraction from synchrotron source is used observe morphology evolve an initial smooth film through various metastable states before reaching state local equilibrium, which point coverage different height structures analyzed and related thickness-dependent surface energy. Rich patterns seen in resulting energy landscape...
Understanding the underlying physical principles that determine internal structure of objects at atomic scale is critical for advancement nanoscale science. We have performed synchrotron x-ray diffraction studies to structural properties smooth Pb films with varying thicknesses 6 18 monolayers deposited on a Si(111) substrate 110 K. observe quasibilayer variations in interlayer spacings consistent charge density oscillations due quantum confinement conduction electrons and surface-interface...
We have used surface x-ray diffraction from a synchrotron source, along with models based upon free-electron gas confined to quantum well, study size effects in the energy of ultrathin Pb films grown on pretreated Si(111) substrates. Films at $110\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ are smooth, but as they annealed near room temperature, their morphology is observed evolving through various metastable states and eventually roughened state local equilibrium. Strong variations stability...
We have studied cw room-temperature lasing behavior of LiNdP4O12. A threshold 360-μW optical excitation power at 0.582-μm wavelength was measured, with 18% conversion efficiency to 1.048-μm radiation 1-mW output. The crystal structure is found be monoclinic (C2/c) rather than orthorhombic as previously reported.