281 research outputs found

    Relativistic J-matrix method

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    The relativistic version of the J-matrix method for a scattering problem on the potential vanishing faster than the Coulomb one is formulated. As in the non-relativistic case it leads to a finite algebraic eigenvalue problem. The derived expression for the tangent of phase shift is simply related to the non-relativistic case formula and gives the latter as a limit case. It is due to the fact that the used basis set satisfies the ``kinetic balance condition''.Comment: 21 pages, RevTeX, accepted for publication in Phys. Rev.

    Strict limit on in-plane ordered magnetic dipole moment in URu2Si2

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    Neutron diffraction is used to examine the polarization of weak static antiferromagnetism in high quality single crystalline URu2Si2. As previously documented, elastic Bragg-like diffraction develops for temperature T<T_{HO}= 17.5 K at q=(100) but not at wave vector transfer q=(001). The peak width indicates correlation lengths \xi_c=230(12) \AA \ and \xi_a=240(15) \AA. The integrated intensity of the T-dependent peaks corresponds to a sample averaged c-oriented staggered moment of \mu_{c}=0.022(1) \mu_B at T=1.7 K. The absence of T-dependent diffraction at q=(001) places a limit \mu_{\perp}<0.0011 \mu_B on an f- or d-orbital based in-plane staggered magnetic dipole moment, which is associated with multipolar orders proposed for URu_2Si_2.Comment: 9 pages, 7 figure

    Incommensurate Spin Ordering and Fluctuations in underdoped La_{2-x}Ba_{x}CuO_{4}

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    Using neutron scattering techniques, we have studied incommensurate spin ordering as well as low energy spin dynamics in single crystal underdoped \LBCO with x∼\sim0.095 and 0.08; high temperature superconductors with TC∼_C \sim 27 K and 29 K respectively. Static two dimensional incommensurate magnetic order appears below TN_N=39.5 ±\pm 0.3 K in \LBCO (x=0.095) and a similar temperature for x=0.08 within the low temperature tetragonal phase. The spin order is unaffected by either the onset of superconductivity or the application of magnetic fields of up to 7 Tesla applied along the c-axis in the x=0.095 sample. Such magnetic field {\it independent} behaviour is in marked contrast with the field induced enhancement of the staggered magnetisation observed in the related \LSCO system, indicating this phenomenon is not a universal property of cuprate superconductors. Surprisingly, we find that incommensurability δ\delta is only weakly dependent on doping relative to \LSCO. Dispersive excitations in \LBCO (x=0.095) at the same incommensurate wavevector persist up to at least 60 K. The dynamical spin susceptibility of the low energy spin excitations saturates below \tc, in a similar manner to that seen in the superconducting state of La2_2CuO4+y_{4+y}.Comment: 9 pages, 7 figures, submitted to PRB, figures update

    Poly(n-butyl Methacrylate) with Primary Amine End Groups for Supporting Cell Adhesion and Proliferation of Renal Epithelial Cells

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    Polymer coatings that support epithelial cell culture have been developed. Ozonolysis and subsequent work up of poly(butyl methacrylate-co-butadiene) copolymers is used to form oligomers with carboxylic acid end groups, which are then further reacted with diamines to provide poly(butyl methacrylate)s with primary amine end groups. The polymers are cast as films and used as cell culture substrates for human dermal fibroblasts and human renal epithelial cells. Fibroblast and epithelial cells adhere and proliferate on acid functional materials but on amine functional films epithelial cells show greater viability than fibroblasts

    Zn-induced spin dynamics in overdoped La2−x_{2-x}Srx_xCu1−y_{1-y}Zny_yO4_4

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    Spin fluctuations and the local spin susceptibility in isovalently Zn-substituted La2−x_{2-x}Srx_{x}Cu1−y_{1-y}Zny_yO4_4 (x=0.25x=0.25, y≈0.01y\approx0.01) are measured via inelastic neutron scattering techniques. As Zn2+^{2+} is substituted onto the Cu2+^{2+}-sites, an anomalous enhancement of the local spin susceptibility χ′′(ω)\chi^{\prime\prime}(\omega) appears due to the emergence of a commensurate antiferromagnetic excitation centered at wave vector \textbf{Q}=(π,π,0)=(\pi, \pi, 0) that coexists with the known incommensurate SDW excitations at \textbf{Q}HK=(π±δ,π),(π,π±δ)_{HK}=(\pi\pm\delta,\pi), (\pi,\pi\pm\delta). Our results support a picture of Zn-induced antiferromagnetic (AF) fluctuations appearing through a local staggered polarization of Cu2+^{2+}-spins, and the simultaneous suppression of Tc_c as AF fluctuations are slowed in proximity to Zn-impurities suggests the continued importance of high energy AF fluctuations at the far overdoped edge of superconductivity in the cuprates.Comment: 10 pages, 8 figure

    Spin ordering and electronic texture in the bilayer iridate Sr3_3Ir2_2O7_7

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    Through a neutron scattering, charge transport, and magnetization study, the correlated ground state in the bilayer iridium oxide Sr3_3Ir2_2O7_7 is explored. Our combined results resolve scattering consistent with a high temperature magnetic phase that persists above 600 K, reorients at the previously defined TAF=280T_{AF}=280 K, and coexists with an electronic ground state whose phase behavior suggests the formation of a fluctuating charge or orbital phase that freezes below T∗≈70T^{*}\approx70 K. Our study provides a window into the emergence of multiple electronic order parameters near the boundary of the metal to insulator phase transition of the 5d Jeff=1/2J_{eff}=1/2 Mott phase.Comment: Revised text and figures. 4 pages, 4 figure

    Magnetic ground state and magnon-phonon interaction in multiferroic h-YMnO3_3

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    Inelastic neutron scattering has been used to study the magneto-elastic excitations in the multiferroic manganite hexagonal YMnO3_3. An avoided crossing is found between magnon and phonon modes close to the Brillouin zone boundary in the (a,b)(a,b)-plane. Neutron polarization analysis reveals that this mode has mixed magnon-phonon character. An external magnetic field along the cc-axis is observed to cause a linear field-induced splitting of one of the spin wave branches. A theoretical description is performed, using a Heisenberg model of localized spins, acoustic phonon modes and a magneto-elastic coupling via the single-ion magnetostriction. The model quantitatively reproduces the dispersion and intensities of all modes in the full Brillouin zone, describes the observed magnon-phonon hybridized modes, and quantifies the magneto-elastic coupling. The combined information, including the field-induced magnon splitting, allows us to exclude several of the earlier proposed models and point to the correct magnetic ground state symmetry, and provides an effective dynamic model relevant for the multiferroic hexagonal manganites.Comment: 12 pages, 10 figure

    Towards Extending CityGML for Property Valuation: Property Valuation ADE

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    This paper introduces Property Valuation Application Domain Extension (ADE) within CityGML 3.0, aiming to integrate relevant indoor and outdoor 3D variables (cost estimation, view quality, etc.) for accurate property valuation. Current models lack the necessary features for this specific application. Leveraging IFC data for indoor elements, this ADE extends CityGML, addressing the existing gap. This paper identifies and categorizes data requirements, leading to the conceptualization and development of the model. By enriching CityGML 3.0 with IFC data, the approach introduces new features like the "Property Unit" to ensure adaptability across diverse valuation scenarios. Despite encountering data integrability challenges, we here commit to refining the model and overcoming these obstacles. A preliminary implementation using CityJSON demonstrates successful integration and paves the way for future implementation. These include developing an API platform and establishing an official repository to facilitate practical usability and scalability. This research significantly contributes to advancing property valuation processes by providing accurate valuations for stakeholders and promoting the use of 3D urban data in domain-specific extensions
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