12,941 research outputs found

    Infrared Hall conductivity of Na0.7_{0.7}CoO2_2

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    We report infrared Hall conductivity σxy(ω)\sigma_{xy}(\omega) of Na0.7_{0.7}CoO2_2 thin films determined from Faraday rotation angle θF\theta_{F} measurements. σxy(ω)\sigma_{xy}(\omega) exhibits two types of hole conduction, Drude and incoherent carriers. The coherent Drude carrier shows a large renormalized mass and Fermi liquid-like behavior of Hall scattering rate, γHaT2\gamma_{H} \sim aT^{2}. The spectral weight is suppressed and disappears at T = 120K. The incoherent carrier response is centered at mid-IR frequency and shifts to lower energy with increasing T. Infrared Hall constant is positive and almost independent of temperature in sharp contrast with the dc-Hall constant.Comment: 5 Pages, 5 Figures. Author list corrected in metadata only, paper is unchange

    Kinetically-controlled thin-film growth of layered β\beta- and γ\gamma-Nax_{x}CoO2_{2} cobaltate

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    We report growth characteristics of epitaxial β\beta-Na0.6_{0.6}CoO2_{2} and γ\gamma-Na0.7_{0.7}CoO2_{2} thin films on (001) sapphire substrates grown by pulsed-laser deposition. Reduction of deposition rate could change structure of Nax_{x}CoO2_{2} thin film from β\beta-phase with island growth mode to γ\gamma-phase with layer-by-layer growth mode. The γ\gamma-Na0.7_{0.7}CoO2_{2} thin film exhibits spiral surface growth with multiterraced islands and highly crystallized texture compared to that of the β\beta-Na0.6_{0.6}CoO2_{2} thin film. This heterogeneous epitaxial film growth can give opportunity of strain effect of physical properties and growth dynamics of Nax_{x}CoO2_{2} as well as subtle nature of structural change.Comment: accepted for publication in Applied Physics Letter

    Unusual superexchange pathways in a Ni triangular lattice of NiGa2_2S4_4 with negative charge-transfer energy

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    We have studied the electronic structure of the Ni triangular lattice in NiGa2_2S4_4 using photoemission spectroscopy and subsequent model calculations. The cluster-model analysis of the Ni 2pp core-level spectrum shows that the S 3pp to Ni 3dd charge-transfer energy is \sim -1 eV and the ground state is dominated by the d9Ld^9L configuration (LL is a S 3pp hole). Cell perturbation analysis for the NiS2_2 triangular lattice indicates that the strong S 3pp hole character of the ground state provides the enhanced superexchange interaction between the third nearest neighbor sites.Comment: 10 pages, 5 figures, accepted to PR

    Species Differentiation Of Fish Samples By Restriction Fragment Length Polymorphism Analysis Of Cytochrome B Gene

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    Metode pengukuran polimorfisme fragmen hasil pemotongan produkreaksi polimorfik berantai oleh enzim restriksi spesifik (polymerase chainreaction-restriction fragment length polymorphism, RFLP-PCR) telah digunakanuntuk membedakan beberapa jenis ikan mentah. Situs cytochrome b mitokondria,yang diamplifikasi oleh primer universal, dipotong menggunakan empat enzimrestriksi (Bfa I, Hinf I, Msp I, Mbo II) sehingga dapat dianalisa fragment-fragmentpendeknya. Hasil yang diperolah dari pemotongan oleh enzim restriksi tersebutternyata dapat digunakan untuk membedakan tiap jenis ikan sampel. Hasilpenelitian ini menunjukkan bahwa PCR dan RFLP-PCR merupakan metode yangsensitif dan dapat dilakukan dalam waktu singkat untuk membedakan berbagaijenis ikan mentah

    Catalysis in Action via Elementary Thermal Operations

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    We investigate catalysis in the framework of elementary thermal operations, making use of its unique advantages to illuminate catalytic dynamics. As groundwork, we establish new technical tools that improve the computability of state transition rules for elementary thermal operations, in particular, providing a full characterization of state transitions for a qutrit system. Using these tools in conjunction with numerical methods, we find that by adopting even just a qubit catalyst, one can significantly enlarge the set of state transitions for a qutrit system, largely closing the gap of reachable states between elementary thermal operations and generic thermal operations. In addition, we decompose catalytic transitions into time-resolved evolution, from which the nonequilibrium free energy exchanges are tracked. Our results document the existence of simple and practicable catalytic advantage in thermodynamics, and demonstrate a way to analyse the mechanism of catalytic processes.Comment: 15+19 pages; 9 figures; comments are welcome

    Signature of Carrier-Induced Ferromagnetism in Ti_{1-x}Co_{x}O_{2-delta}: Exchange Interaction Between High-Spin Co 2+ and the Ti 3d Conduction Band

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    X-ray photoemission spectroscopy measurements were performed on thin-film samples of rutile Ti_{1-x}Co_{x}O_{2-delta} to reveal the electronic structure. The Co 2p core level spectra indicate that the Co ions take the high-spin Co 2+ configuration, consistent with substitution on the Ti site. The high spin state and the shift due to the exchange splitting of the conduction band suggest strong hybridization between carriers in the Ti 3d t2g band and the t2g states of the high-spin Co 2+. These observations support the argument that room temperature ferromagnetism in Ti_{1-x}Co_{x}O_{2-delta} is intrinsic.Comment: 4 pages, 5 figures. Accepted for publication in Physical Review Letter

    JOINT MOMENTS IN GAIT WITH SIDED LOAD CARRIAGE

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    INTRODUCTION: The present study investigated the biomechanical effects of weight variation for sided load carriage during walking upon joint moments by using the tracker agent and joint driving dynamic analysis

    Gourd-shaped hole array germanium (Ge)-on-insulator photodiodes with improvedresponsivity and specific detectivity at 1,550 nm

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    Gourd-shaped hole array germanium (Ge) vertical p-i-n photodiodes were designed and demonstrated on a germanium-on-insulator (GOI) substrate with the excellent responsivity of 0.74 A/W and specific detectivity of 3.1 × 1010 cm·Hz1/2/W. It is calculated that the gourd-shaped hole design provides a higher optical absorption compared to a cylinder-shaped hole design. As a result, the external quantum efficiency for the gourd-shaped hole array photodetector was enhanced by ∼2.5× at 1,550 nm, comparing with hole-free array photodetectors. In addition, the extracted specific detectivity is superior to that of commercial bulk Ge photodiodes. The 3-dB bandwidth for the hole array photodetectors is improved by ∼10% due to a lower device capacitance. This work paves the way for low-cost and high-performance CMOS compatible photodetectors for Si-based photonic-integrated circuits

    The Dropping of In-Medium Hadron Mass in Holographic QCD

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    We study the baryon density dependence of the vector meson spectrum using the D4/D6 system together with the compact D4 baryon vertex. We find that the vector meson mass decreases almost linearly in density at low density for small quark mass, but saturates to a finite non-zero value for large density. We also compute the density dependence of the η\eta\prime mass and the η\eta\prime velocity. We find that in medium, our model is consistent with the GMOR relation up to a few times the normal nuclear density. We compare our hQCD predictions with predictions made based on hidden local gauge theory that is constructed to model QCD.Comment: 20 pages, 7 figure
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