The Experts below are selected from a list of 3804 Experts worldwide ranked by ideXlab platform

Yuping Sun - One of the best experts on this subject based on the ideXlab platform.

Renhuai Wei - One of the best experts on this subject based on the ideXlab platform.

Joel E Moore - One of the best experts on this subject based on the ideXlab platform.

  • doping dependence of thermopower and thermoelectricity in strongly correlated materials
    Applied Physics Letters, 2007
    Co-Authors: Subroto Mukerjee, Joel E Moore
    Abstract:

    The search for efficient semiconductor thermoelectrics has been greatly aided by theoretical modeling of electron and phonon transports in bulk materials and nanocomposites. Recent experiments have studied thermoelectric transport in thermoelectrics that are “strongly correlated” and derived by doping Mott insulators. Here a unified theory of electrical and thermal transport in the atomic and “Heikes” limit is applied to understand recent experiments on sodium Cobaltate and other doped Mott insulators at room temperature and above. For optimal electron filling, a broad class of narrow-bandwidth correlated materials is shown to have thermoelectric power factors as high as in the best semiconductors.The search for efficient semiconductor thermoelectrics has been greatly aided by theoretical modeling of electron and phonon transports in bulk materials and nanocomposites. Recent experiments have studied thermoelectric transport in thermoelectrics that are “strongly correlated” and derived by doping Mott insulators. Here a unified theory of electrical and thermal transport in the atomic and “Heikes” limit is applied to understand recent experiments on sodium Cobaltate and other doped Mott insulators at room temperature and above. For optimal electron filling, a broad class of narrow-bandwidth correlated materials is shown to have thermoelectric power factors as high as in the best semiconductors.

D. Grebille - One of the best experts on this subject based on the ideXlab platform.

  • Direct observation of strong correlations near the band insulator regime of Bi misfit Cobaltates
    Physical Review B, 2007
    Co-Authors: Véronique Brouet, A. Nicolaou, Michele Zacchigna, Antonio Tejeda, L. Patthey, Sylvie Hébert, Wataru Kobayashi, Hervé Muguerra, D. Grebille
    Abstract:

    We establish with angle-resolved photoemission spectroscopy (ARPES) that the electronic structure near the Fermi level of the ``misfit'' Cobaltate $[{\mathrm{Bi}}_{2}{\mathrm{Ba}}_{2}{\mathrm{O}}_{4}]∙{[\mathrm{Co}{\mathrm{O}}_{2}]}_{\ensuremath{\sim}2}$ is similar to that of Na Cobaltates ${\mathrm{Na}}_{x}\mathrm{Co}{\mathrm{O}}_{2}$. Both families of compounds contain triangular Co planes but in a different three-dimensional environment. We propose that the peculiar ARPES line shape of all Cobaltates is of the ``peak-dip-hump'' type, due to strong many-body effects. We detect a progressive transfer of spectral weight from the quasiparticle feature near ${E}_{F}$ to a broad hump in misfit phases where Ba is replaced by Sr or Ca. This indicates stronger many-body interactions in proximity to the band insulator regime, which we attribute to the presence of unusual magnetic excitations.

Sylvie Hébert - One of the best experts on this subject based on the ideXlab platform.

  • Interplay between magnetic properties and thermoelectricity in misfit and Na Cobaltates
    Physical Review B, 2007
    Co-Authors: Julien Bobroff, Sylvie Hébert, G. Lang, Philippe Mendels, Denis Pelloquin, Antoine Maignan
    Abstract:

    We present a comparative study of CoO2 layers in the Bi-misfit and NaxCoO2 Cobaltates. Co NMR measures the intrinsic susceptibility of the Co layers and is not affected by spurious contributions. At low dopings where room-temperature thermopower (TEP) is large, Curie-Weiss susceptibilities are observed in both materials. But NMR and muSR experiments find neither charge nor spin order down to low temperatures in Bi-misfit, in contrast to the case of NaxCoO2. This demonstrates that metallicity, charge and magnetic orders are specific of the Na layers in NaxCoO2 whereas strong correlations are generic of the Cobaltates physics and could explain the large TEP.

  • Direct observation of strong correlations near the band insulator regime of Bi misfit Cobaltates
    Physical Review B, 2007
    Co-Authors: Véronique Brouet, A. Nicolaou, Michele Zacchigna, Antonio Tejeda, L. Patthey, Sylvie Hébert, Wataru Kobayashi, Hervé Muguerra, D. Grebille
    Abstract:

    We establish with angle-resolved photoemission spectroscopy (ARPES) that the electronic structure near the Fermi level of the ``misfit'' Cobaltate $[{\mathrm{Bi}}_{2}{\mathrm{Ba}}_{2}{\mathrm{O}}_{4}]∙{[\mathrm{Co}{\mathrm{O}}_{2}]}_{\ensuremath{\sim}2}$ is similar to that of Na Cobaltates ${\mathrm{Na}}_{x}\mathrm{Co}{\mathrm{O}}_{2}$. Both families of compounds contain triangular Co planes but in a different three-dimensional environment. We propose that the peculiar ARPES line shape of all Cobaltates is of the ``peak-dip-hump'' type, due to strong many-body effects. We detect a progressive transfer of spectral weight from the quasiparticle feature near ${E}_{F}$ to a broad hump in misfit phases where Ba is replaced by Sr or Ca. This indicates stronger many-body interactions in proximity to the band insulator regime, which we attribute to the presence of unusual magnetic excitations.