A5014942401- Glass properties and applications
- Material Dynamics and Properties
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- High-pressure geophysics and materials
- Boron and Carbon Nanomaterials Research
- Ferroelectric and Piezoelectric Materials
- Silicon Nanostructures and Photoluminescence
- Luminescence Properties of Advanced Materials
- Inorganic Chemistry and Materials
- MXene and MAX Phase Materials
- Metallic Glasses and Amorphous Alloys
- Nuclear materials and radiation effects
- Building materials and conservation
- Acoustic Wave Resonator Technologies
- Metal-Organic Frameworks: Synthesis and Applications
- Diamond and Carbon-based Materials Research
- Semiconductor materials and devices
- Chemical Thermodynamics and Molecular Structure
- Recycling and utilization of industrial and municipal waste in materials production
- Electronic and Structural Properties of Oxides
- Metal and Thin Film Mechanics
- Silicon and Solar Cell Technologies
- Photorefractive and Nonlinear Optics
- Semiconductor materials and interfaces
Carnegie Institution for Science
2017-2020
Geophysical Laboratory
2017-2020
Rensselaer Polytechnic Institute
2011-2018
Abstract Silica glass has been shown in numerous studies to possess significant capacity for permanent densification under pressure at different temperatures form high density amorphous (HDA) silica. However, it is unknown what extent the processes leading irreversible of silica cold-compression room temperature and hot-compression (e.g., near transition temperature) are common nature. In this work, a technique was used quench from (1100 °C) (up 8 GPa) conditions, which leads increase ~25%...
The realization of a novel guest/host carbon-boron sp 3 framework opens the door for new class 3D carbon-based materials.
Abstract An emulated platelet geometry (or reflection-induced geometry) is employed to collect photons scattered from both longitudinal and transverse acoustic waves travelling within a bulk transparent sample sitting on reflective Pt plate. Temperature of the was controlled with Linkam TS1500 optical furnace (maximum temperature 1500 °C). This simple convenient set-up allows full determination elastic constants materials in situ as function Brillouin light scattering. Structural information...
In situ Raman and Brillouin light scattering techniques were used to study thermally induced high-density amorphous (HDA) low-density (LDA) transition in silica glass densified hot compression (up 8 GPa at 1100 °C). Hot-compressed samples are shown retain structural mechanical stability through 600 °C or greater, with reduced sensitivity elastic response temperature as compared pristine glass. Given sufficient thermal energy overcome the barrier, compacted structure of HDA reverts back LDA...
Abstract We report a carbon‐boron clathrate with composition 2 La@B 6 C (LaB 3 ). Like recently reported SrB , [1] single‐crystal X‐ray diffraction and computational modelling indicate that the isostructural La member crystallizes in cubic bipartite sodalite structure (Type‐VII clathrate) atoms encapsulated within truncated octahedral cages composed of alternating carbon boron atoms. The covalent nature B−C bonding results hard, incompressible framework, owing to balanced electron count, 3+...
Abstract
In situ Brillouin light scattering measurements with a spatial resolution of ~1 μm have been carried out to study the elastic moduli silica glass fibers in single two‐point bend experiment nominal strains 7% both tensile and compressive regions. Such data are necessary order convert failure obtained from experiments into stress. For first time, neutral axis shift bent fiber was observed our measurements, more deforming compression than tension, resulting nonlinear behavior glass....
Si24 is a new, open-framework silicon allotrope that metastable at ambient conditions. Unlike diamond cubic silicon, which an indirect-gap semiconductor, has quasidirect gap near 1.4 eV, presenting new opportunities for optoelectronic and solar energy conversion devices. Previous studies indicate Na can diffuse from micron-sized grains of high-pressure Na4Si24 precursor to create powders Remarkably, we demonstrate here remains highly mobile within large (~100 µm) single crystals. readily...
Na4Si24 is the precursor to Si24, a recently discovered allotrope of silicon. With quasidirect band gap near 1.3 eV, Si24 has potential transform silicon-based optoelectronics including solar energy conversion. However, lack large, pure crystals prevented characterization intrinsic properties and delayed deposition-based metastable growth efforts. Here, we report an optimized synthesis methodology for single-crystalline with approaching millimeter-size scale conditions 9 GPa 1123 K....
Abstract We report a carbon‐boron clathrate with composition 2 La@B 6 C (LaB 3 ). Like recently reported SrB , [1] single‐crystal X‐ray diffraction and computational modelling indicate that the isostructural La member crystallizes in cubic bipartite sodalite structure (Type‐VII clathrate) atoms encapsulated within truncated octahedral cages composed of alternating carbon boron atoms. The covalent nature B−C bonding results hard, incompressible framework, owing to balanced electron count, 3+...
Permanent density increase of silica glass was used to calibrate pressure generation delivered by cupped sintered diamond anvils ('dimple anvils') [Haberl B, Molaison JJ, Neuefeind JC, et al. Simple modified Bridgman anvil design for high synthesis and neutron scattering. High Press. Res. submitted] within the Paris-Edinburgh press between approximately 9 20 GPa. Raman spectral changes recovered with increased were determine maximum reached following an established calibration curve...
We study the aging and Mn doping effect on third generation lead based relaxor single crystals. measured polarization (PE) strain with applied field two perpendicular orientations of rhombohedral pseudocubic [001] poled crystal. To understand these effects along average dipoles/defect dipoles direction, we adopt a simple model direction cosine sine strain. found that when PE measurement is to defect dipoles, double loop observed, it parallel an asymmetric response observed. propose varied in...
We predict a new candidate high-temperature high-pressure structure of FeSiO$_3$ with space-group symmetry Cmmm by applying an evolutionary algorithm within DFT+U that we call post-perovskite II (PPv-II). An exhaustive search found no other competitive structures ABO$_3$ composition. compared the X-ray diffraction (XRD) pattern PPv-II experimental results recently reported "H-phase" (Fe,Mg)SiO$_3$. The intensities and positions two main peaks compare well those H-phase. also calculated...