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Results for “Pd-Te”

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 OSTI2023

Understanding palladium–tellurium cluster formation on WTe2: From a kinetically hindered distribution to thermodynamically controlled monodispersity

Abstract A fundamental understanding of the transition metal dichalcogenide (TMDC)–metal interface is critical for their utilization in a broad range of applications. We investigate how the deposition of palladium (Pd), as a model metal, on WTe2(001), leads to the assembly of Pd into clusters and nanoparticles. Using X-ray photoemission spectroscopy, scanning tunneling microscopy imaging, and ab initio simulations, we find that Pd nucleation is driven by the interaction with and the availability of mobile excess tellurium (Te) leading to the formation of Pd-Te clusters at room temperature. Surprisingly, the nucleation of Pd-Te clusters is not affected by intrinsic surface defects, even at elevated temperatures. Upon annealing, the Pd-Te nanoclusters adopt an identical nanostructure and are stable up to ∼523 K. Density functional theory calculations provide a foundation for our understanding of the mobility of Pd and Te atoms, preferential nucleation of Pd-Te clusters, and the origin of their annealing-induced monodispersity. These results highlight the role the excess chalcogenide atoms may play in the metal deposition process. More broadly, the discoveries of synthetic pathways yielding thermally robust monodispersed nanostructures on TMDCs are critical to the manufacturing of novel quantum and microelectronics devices and catalytically active nano-alloy centers.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Fractional AC Josephson effect in a topological insulator proximitized by a self-formed superconductor

A lateral Josephson junction in which the surface of a 3D topological insulator serves as the weak link should support topologically protected excitations related to Majorana fermions. The resulting 4π-periodic current-phase relationship could be detected under high-frequency excitation by the suppression of odd Shapiro steps. Here, in this study, we demonstrate such devices through the self-formation of a Pd-Te superconducting layer from a telluride topological insulator, and observe suppressed first and third Shapiro steps. Other devices, including those where the Pd-Te layer is bolstered by an additional Al layer, show no suppression of Shapiro steps, a difference supported by simulations. Though we rule out the known trivial causes of suppressed Shapiro steps in our devices, we nevertheless argue that corroborating measurements and disorder-aware theoretical descriptions of these systems are needed before confidently claiming the observation of Majorana states.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Three-dimensional microstructural characterization of FBR MOX fuel and the contribution of microstructural features to the thermal conductivity of the fuel

Combination of microstructural characterization, property measurements, and phase field modeling is used to investigate fast breeder reactor (FBR) mixed oxide (MOX) fuel irradiated to burnup of 13.7% fissions per initial metal atom (FIMA). Here, the fuel was characterized at different radial locations, which revealed that grey phase can be present in the central region if it nucleates on five metal precipitates (FMPs). In addition, in the mid-radial region FMPs do not diffuse out of the region once formed and the size of Pd–Te precipitates is dictated by the porosity present in the region. Thermal conductivity measurements were conducted as a function of radial location and the microstructure of the fuel was correlated with the observed trend. Reconstructions of the 3D solid and gaseous fission product structures in different regions of the fuel were used to simulate the effective thermal conductivity (ETC) of the respective regions and determine which microstructural feature has the strongest impact on thermal conductivity. Based on conducted assessment, FMPs and Pd-Te precipitates improve local conductivity of central and mid-radial regions even in the presence of grey phase, but defects are primary contributor to the degradation of thermal conductivity on the periphery of the fuel.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Materials Data on Te7Pd20 by Materials Project

Pd20Te7 is beta Plutonium-derived structured and crystallizes in the trigonal R-3 space group. The structure is three-dimensional. there are four inequivalent Pd sites. In the first Pd site, Pd is bonded in a 2-coordinate geometry to three Pd and three equivalent Te atoms. There are two shorter (2.89 Å) and one longer (2.98 Å) Pd–Pd bond lengths. There are a spread of Pd–Te bond distances ranging from 2.67–2.88 Å. In the second Pd site, Pd is bonded in a 10-coordinate geometry to seven Pd and three equivalent Te atoms. There are one shorter (2.73 Å) and three longer (2.95 Å) Pd–Pd bond lengths. All Pd–Te bond lengths are 2.69 Å. In the third Pd site, Pd is bonded in a 3-coordinate geometry to five Pd and three Te atoms. There are a spread of Pd–Pd bond distances ranging from 2.89–2.97 Å. There are a spread of Pd–Te bond distances ranging from 2.70–2.93 Å. In the fourth Pd site, Pd is bonded in a 12-coordinate geometry to eight Pd and four Te atoms. Both Pd–Pd bond lengths are 3.12 Å. There are a spread of Pd–Te bond distances ranging from 2.71–2.90 Å. There are two inequivalent Te sites. In the first Te site, Te is bonded in a cuboctahedral geometry to twelve Pd atoms. In the second Te site, Te is bonded in a 9-coordinate geometry to nine Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TePd by Materials Project

PdTe is Tungsten Carbide-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Pd2+ is bonded to six equivalent Te2- atoms to form a mixture of edge, face, and corner-sharing PdTe6 octahedra. The corner-sharing octahedral tilt angles are 51°. All Pd–Te bond lengths are 2.82 Å. Te2- is bonded in a 6-coordinate geometry to six equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te2Pd3 by Materials Project

Pd3Te2 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Pd sites. In the first Pd site, Pd is bonded in a 5-coordinate geometry to four equivalent Pd and five Te atoms. There are two shorter (2.93 Å) and two longer (3.03 Å) Pd–Pd bond lengths. There are one shorter (2.66 Å) and four longer (2.85 Å) Pd–Te bond lengths. In the second Pd site, Pd is bonded in a 5-coordinate geometry to five Pd and five Te atoms. There are one shorter (2.96 Å) and two longer (3.17 Å) Pd–Pd bond lengths. There are three shorter (2.75 Å) and two longer (2.91 Å) Pd–Te bond lengths. There are two inequivalent Te sites. In the first Te site, Te is bonded in a body-centered cubic geometry to eight Pd atoms. In the second Te site, Te is bonded in a 7-coordinate geometry to seven Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te3Pd13 by Materials Project

Pd13Te3 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. there are four inequivalent Pd sites. In the first Pd site, Pd is bonded in a 1-coordinate geometry to four Pd and one Te atom. There are one shorter (3.01 Å) and three longer (3.10 Å) Pd–Pd bond lengths. The Pd–Te bond length is 2.58 Å. In the second Pd site, Pd is bonded to ten Pd and four equivalent Te atoms to form distorted corner-sharing PdTe4Pd10 tetrahedra. All Pd–Pd bond lengths are 3.07 Å. All Pd–Te bond lengths are 2.79 Å. In the third Pd site, Pd is bonded in a 2-coordinate geometry to three Pd and two equivalent Te atoms. Both Pd–Pd bond lengths are 2.88 Å. Both Pd–Te bond lengths are 2.71 Å. In the fourth Pd site, Pd is bonded in a 8-coordinate geometry to twelve Pd and two equivalent Te atoms. Both Pd–Te bond lengths are 2.79 Å. There are two inequivalent Te sites. In the first Te site, Te is bonded in a body-centered cubic geometry to eight Pd atoms. In the second Te site, Te is bonded in a body-centered cubic geometry to eight Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TePd3 by Materials Project

Pd3Te is alpha bismuth trifluoride structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Pd sites. In the first Pd site, Pd is bonded to eight Pd and four equivalent Te atoms to form PdTe4Pd8 cuboctahedra that share corners with twelve equivalent PdTe4Pd8 cuboctahedra, edges with eight equivalent TePd12 cuboctahedra, edges with sixteen PdTe4Pd8 cuboctahedra, faces with four equivalent TePd12 cuboctahedra, and faces with fourteen PdTe4Pd8 cuboctahedra. There are four shorter (2.86 Å) and four longer (2.98 Å) Pd–Pd bond lengths. All Pd–Te bond lengths are 2.86 Å. In the second Pd site, Pd is bonded to eight equivalent Pd and four equivalent Te atoms to form PdTe4Pd8 cuboctahedra that share corners with four equivalent PdTe4Pd8 cuboctahedra, corners with eight equivalent TePd12 cuboctahedra, edges with twenty-four PdTe4Pd8 cuboctahedra, faces with six equivalent TePd12 cuboctahedra, and faces with twelve PdTe4Pd8 cuboctahedra. All Pd–Te bond lengths are 2.98 Å. Te is bonded to twelve Pd atoms to form TePd12 cuboctahedra that share corners with four equivalent TePd12 cuboctahedra, corners with eight equivalent PdTe4Pd8 cuboctahedra, edges with eight equivalent TePd12 cuboctahedra, edges with sixteen equivalent PdTe4Pd8 cuboctahedra, faces with four equivalent TePd12 cuboctahedra, and faces with fourteen PdTe4Pd8 cuboctahedra.

36 MATERIALS SCIENCE↗