Point defect scattering

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August undefined, 2024

WebPoint defects in solids such as vacancy and dopants often cause large thermal resistance. Since the lattice site occupied by a point defect has a much smaller size than phonon … Webhas been revealed. By further introducing the point defects without affecting the grain size via neutron irradiation, the thermally activated electrical conductivity can be reproduced. Our results demonstrate that the point defects scattering of electrons is important in the n-type Mg 3 Sb 2-based materials. Keywords: Thermoelectric materials ...

Thermal conductivity of α -U with point defects - AIP Publishing

WebJul 6, 2015 · The design of thermoelectric materials often involves the integration of point defects (alloying) as a route to reduce the lattice thermal conductivity. Classically, the point defect scattering strength follows from simple considerations such as mass contrast and the presence of induced strain fields ( e.g. radius contrast, coordination changes). WebAssuming the scattering of phonons by a point defect is independent of other point defects, the phonon-defect scattering rate is . d. s, s s s 1 d f τ ′′ ′′ = Γ∑ qq q q, (5) where f is the volumetric fraction of point defects. 2.1.2 Born approximation and Klemens’ model using realistic phonon dispersion cynthia paffen

Ab initio phonon point defect scattering and thermal transport in ...

WebOct 29, 2010 · A semi-empirical tight-binding Hamiltonian based on density functional theory is used to study scattering of defects in H-passivated (110)SiNWs. The effect of surface … WebAug 1, 2024 · Additional point-defect scattering of phonons is also induced by Sb alloying. Benefitting from the enhanced power factor, decreased lattice thermal conductivity, and … cynthia padilla facebook

Interstitial Point Defect Scattering Contributing to High ...

Phonon Scattering by Distortion About a Point Defect

WebJan 16, 2024 · a The schematic of point defect scattering. When the entire phonon wavelength λ is larger than the pore size, the pore can be regarded as a point defect, and … WebApr 12, 2024 · This dependence was approximated taking into account phonon scattering by the boundaries of the sample, as well as scattering by dislocations, point defects, and phonon-phonon scattering. When comparing the parameters of this approximation with similar parameters for literature data for a freshly prepared polycrystalline sample, it … cynthia paduchWebSimultaneous determination of the lamellar morphological length scale and the grain size of several low molecular weight heterogeneous styrene−butadiene block copolymers was … cynthia padgett

"WebOct 14, 2024 · Unlike point defects, these high-dimensional defects such as dislocations contribute to enhancing the phonon scattering without sacrificing the carrier mobility 40, thereby bringing... " - Point defect scattering

Point defect scattering

Webthe optical scattering of incident light caused by large-sized particles in the nanocrystalline matrix as well as by the statistical clusters of sintering defects in the nanocrystalline solid … WebThe scattering power of defect pairs as a function of separation is therefore investigated as a two-center scattering problem, and the theory is found to predict the observed insensitivity of scattering cross section to defect separation for all realizable separations of the defects. (auth) Physical Review (U.S.) Superseded in part by Phys. Rev.

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WebJan 4, 2024 · Abstract. We study the scattering of phonons from point defects and their effect on lattice thermal conductivity κ using a parameter-free ab initio Green's function methodology. Specifically, we ... WebThe role of the point-defect scattering relaxation rate has been studied in the lattice thermal conductivity of an insulator by calculating the lattice thermal conductivity of GaAs for the different values of the point-defect scattering strength.

WebFeb 6, 2012 · The design of thermoelectric materials often involves the integration of point defects (alloying) as a route to reduce the lattice thermal conductivity. Classically, the point defect scattering strength follows from simple considerations such as mass contrast and the presence of induced strain fields (e.g. radius contrast, coordination changes). WebMar 9, 2024 · In the present study, we examine the effect of point defects and fission gases on thermal transport in representative actinide oxides used in modern reactors. In particular, oxygen interstitials and Kr/Xe fission gas bubbles are of primary focus. Reverse non-equilibrium molecular dynamics is employed to investigate thermal transport in UO2 and …

WebAug 4, 2015 · The overall effect of the phonon scattering by point defects was to reduce the conductivity by 42% at 12 K and 5% at 300 K for the purer (Damon) sample, and by 74% at 15 K and 21% at 300 K for the more defective (Tan) sample. Above 400 K, the intrinsic conductivity (that of a defect-free and isotope-free sample within the SMRT) is obtained as . WebJul 6, 2015 · The design of thermoelectric materials often involves the integration of point defects (alloying) as a route to reduce the lattice thermal conductivity. Classically, the …

WebOct 22, 2015 · The Raman scattering D-peak in graphene is spatially localised in close proximity to defects. Here, we demonstrate the capability of tip-enhanced Raman spectroscopy (TERS) to probe individual point defects, even for a graphene layer with an extremely low defect density. This is of practical interest for future graphene electronic …

WebPoint defects scatter phonons because of changes in mass and force constants at the defect site; a mass increase and an expansion both lower the local value of the phonon velocity and reinforce the perturbation. ... Phonon Scattering by Distortion About a Point Defect. In: Anderson, A.C., Wolfe, J.P. (eds) Phonon Scattering in Condensed Matter ... cynthia paes san diegoWebApr 2, 2024 · In addition to Umklapp and point defect scattering, it was also estimated the contribution of boundary scattering to κ L. The relaxation time of boundary scattering is given by τ BS = d/v , where d is the average grain size of the sample. Based on XRD and SEM results (Fig. 1b), a value of d = 10–30 μm is estimated. cynthia paffumiWebAug 1, 2024 · A further decreased thermal conductivity is obtained by alloying Sb at the Bi site for the additional point-defect scattering of phonons. This Sb alloying also enhances the density-of-states near the valence band maximum for a larger carrier effective mass, and suppresses the bipolar effect by increasing the carrier concentration and widening ... biltmore area phoenix hotelsWebNov 8, 2024 · The dominant scattering mechanism governing thermal transport in α-U at different temperatures is examined. By including phonon–defect and electron–defect scatterings in the model, we study the effect of point defects including U-vacancy, U-interstitial, and Zr-substitution on the thermal conductivity of α-U. The degradation of ... biltmore art exhibitWebGrassmannian and bosonic Thirring models with jump defects. Grassmannian and bosonic Thirring models with jump defects. Alexis González Aguirre. 2011, Journal of High Energy Physics ... biltmore artworkWebApr 10, 2024 · When local distortions around point defects are strong, standard perturbative approaches fail, and phonon scattering can only be accounted for by an exact Green's function calculation. biltmore arizona weddingWebFrom an intuitive point of view, the point defects cause lattice distortion, around which the periodic potential field is deviated from the normal condition, and consequently become the scatter source of electrons or phonons. cynthia page elmhurst