72 research outputs found
Relação entre bromélias epifÃticas e forófitos em diferentes estádios sucessionais
Ferromagnetism in the Mott Insulator Ba2NaOsO6
Results are presented of single crystal structural, thermodynamic, and reflectivity measurements of the double-perovskite Ba2NaOsO6. These characterize the material as a 5d1 ferromagnetic Mott insulator with an ordered moment of ∼0.2μB per formula unit and TC=6.8(3)  K. The magnetic entropy associated with this phase transition is close to Rln2, indicating that the quartet ground state anticipated from consideration of the crystal structure is split, consistent with a scenario in which the ferromagnetism is associated with orbital ordering.This article is from Physical Review Letters 99 (2007): 1, doi:10.1103/PhysRevLett.99.016404. Posted with permission.</p
Sputtering synthesis and properties of molybdenum nanocrystals and Al/Mo layered nanocomposites
Effect of screening of the electron-phonon interaction on mass renormalization and optical conductivity of the extended Holstein model polarons
An interacting electron-phonon system is considered within the Extended
Holstein model at strong coupling regime and nonadiabatic approximation. It is
assumed that screening of an electron-phonon interaction is due to the excess
electrons in a lattice. An influence of the screening on the mass and optical
conductivity of a lattice polarons is studied. A more general form Yukawa-type
electron-phonon interaction potential potential is accepted and corresponding
forces are derived in a lattice. It is emphasized that the screening effect is
more pronounced at the values of screening radius comparable with a lattice
constant. It is shown that the mass of a lattice polaron obtained using
Yukawa-type electron-phonon interaction potential is less renormalized than
those of the early studied works at the same screening regime. Optical
conductivity of lattice polarons is calculated at different screening regimes.
The screening lowers the value of energy that corresponds to the peak of the
optical conductivity curve. The shift (lowering) is more pronounced at small
values of screening radius too. The factors that give rise to this shift is
briefly discussed.Comment: 8 pages, 10 figures, 1 table. arXiv admin note: substantial text
overlap with arXiv:1308.219
Moisture, thermal and wind measurements over two selected stable and unstable sand dunes in the Indian desert
Evaluation of congestive heart failure in children with rheumatic heart disease as a criterion of rheumatic activity.
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