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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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8 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on FeRe by Materials Project

FeRe crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Re is bonded to six equivalent Re and six equivalent Fe atoms to form ReFe6Re6 cuboctahedra that share corners with eighteen equivalent ReFe6Re6 cuboctahedra, edges with six equivalent ReFe6Re6 cuboctahedra, edges with twelve equivalent FeFe6Re6 cuboctahedra, faces with eight equivalent ReFe6Re6 cuboctahedra, and faces with twelve equivalent FeFe6Re6 cuboctahedra. All Re–Re bond lengths are 2.69 Å. All Re–Fe bond lengths are 2.59 Å. Fe is bonded to six equivalent Re and six equivalent Fe atoms to form FeFe6Re6 cuboctahedra that share corners with eighteen equivalent FeFe6Re6 cuboctahedra, edges with six equivalent FeFe6Re6 cuboctahedra, edges with twelve equivalent ReFe6Re6 cuboctahedra, faces with eight equivalent FeFe6Re6 cuboctahedra, and faces with twelve equivalent ReFe6Re6 cuboctahedra. All Fe–Fe bond lengths are 2.69 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on FeRe(PbO3)2 by Materials Project

Pb2FeReO6 is (Cubic) Perovskite-derived structured and crystallizes in the tetragonal I4 space group. The structure is three-dimensional. Re5+ is bonded to six O2- atoms to form ReO6 octahedra that share corners with six equivalent FeO6 octahedra and faces with eight equivalent PbO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Re–O bond distances ranging from 1.95–1.98 Å. Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent ReO6 octahedra and faces with eight equivalent PbO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Fe–O bond distances ranging from 2.02–2.09 Å. Pb2+ is bonded to twelve O2- atoms to form PbO12 cuboctahedra that share corners with twelve equivalent PbO12 cuboctahedra, faces with six equivalent PbO12 cuboctahedra, faces with four equivalent ReO6 octahedra, and faces with four equivalent FeO6 octahedra. There are a spread of Pb–O bond distances ranging from 2.71–2.98 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to one Re5+, one Fe3+, and four equivalent Pb2+ atoms. In the second O2- site, O2- is bonded in a linear geometry to one Re5+, one Fe3+, and four equivalent Pb2+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to one Re5+, one Fe3+, and four equivalent Pb2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on FeRe(PbO3)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2021

Ultrabroadband Nanocavity of Hyperbolic Phonon–Polaritons in 1D-Like α-MoO 3

The exploitation of phonon–polaritons in nanostructured materials offers a pathway to manipulate infrared (IR) light for nanophotonic applications. Notably, hyperbolic phonon–polaritons (HP 2 ) in polar bidimensional crystals have been used to demonstrate strong electromagnetic field confinement, ultraslow group velocities, and long lifetimes (up to ~12 ps). Here we present nanobelts of α-phase molybdenum trioxide (α-MoO 3 ) as a low-dimensional medium supporting HP 2 modes in the mid- and far-IR ranges. Through real-space nanoimaging techniques with synchrotron and tunable laser IR light, we observe HP 2 Fabry-Perot resonances that demonstrate distinct anisotropic propagation and frequency dependence. We remark an anisotropic propagation that critically depends on the frequency range. Our findings are supported by the convergence of experiment, theory, and numerical simulations. Our work shows that the low dimensionality of natural nanostructured crystals, like α-MoO 3 nanobelts, provides an attractive platform to study polaritonic light–matter interactions and offers appealing cavity properties that could be harnessed in future designs of compact nanophotonic devices.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Paratellurite Nanowires as a Versatile Material for THz Phonon Polaritons

Polaritons, i.e., hybrid quasi-particles of light and matter resonances, have been extensively investigated due to their potential to enhance light-matter interactions. Although polaritonic applications thrive in the mid-infrared range, their extension to the terahertz (THz) range remains limited. Here, we present paratellurite (α-TeO 2 ) nanowires, a versatile material acting as a platform for different types of phonon polaritons. Utilizing synchrotron infrared nanospectroscopy from 10 to 24 THz, we uncover the polaritonic properties of α-TeO 2 nanowires, showcasing their dual functionality as both a Fabry-Pérot cavity and a waveguide for surface phonon polaritons. Furthermore, near-field measurements with a free-electron laser as a THz source reveal a localized optical contrast down to 5.5 THz, an indication of hyperbolic bands. In conclusion, our findings complement the repertoire of polaritonic materials, with significant implications for advancing THz technologies.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Sub-diffractional cavity modes of terahertz hyperbolic phonon polaritons in tin oxide

Abstract Hyperbolic phonon polaritons have recently attracted considerable attention in nanophotonics mostly due to their intrinsic strong electromagnetic field confinement, ultraslow polariton group velocities, and long lifetimes. Here we introduce tin oxide (SnO 2 ) nanobelts as a photonic platform for the transport of surface and volume phonon polaritons in the mid- to far-infrared frequency range. This report brings a comprehensive description of the polaritonic properties of SnO 2 as a nanometer-sized dielectric and also as an engineered material in the form of a waveguide. By combining accelerator-based IR-THz sources (synchrotron and free-electron laser) with s-SNOM, we employed nanoscale far-infrared hyper-spectral-imaging to uncover a Fabry–Perot cavity mechanism in SnO 2 nanobelts via direct detection of phonon-polariton standing waves. Our experimental findings are accurately supported by notable convergence between theory and numerical simulations. Thus, the SnO 2 is confirmed as a natural hyperbolic material with unique photonic properties essential for future applications involving subdiffractional light traffic and detection in the far-infrared range.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

Two-dimensional talc as a natural abundant ultra-broadband hyperbolic material

Here, we demonstrate that two-dimensional talc, a naturally abundant phyllosilicate mineral, supports hyperbolic phonon-polaritons (HPhPs) across the mid- and far-infrared wavelengths. Using scattering scanning near-field optical microscopy (s-SNOM) and synchrotron infrared nano-spectroscopy (SINS), we reveal tunable HPhP modes in talc flakes with long lifetimes, high confinement, and quality factors of up to 5. We further observe Fabry–Pérot cavity modes in tapered flakes, confirmed by simulations and analytical modeling. Compared to synthetic crystals, talc offers an ultra-broadband, low-cost, and sustainable platform for infrared nanophotonics and optoelectronics.

36 MATERIALS SCIENCE↗